Apparatus and method for inter-band pairing of carriers for time division duplex transmit- and receive-switching and its application to multiplexing of different transmission time intervals

ABSTRACT

Aspects of the present disclosure provide for the pairing of an inter-band carrier with a time division duplex (TDD) carrier. If the paired band is a frequency division duplex (FDD) band, then base stations and mobile devices may transmit and receive additional thin control channels on FDD carriers to enable full duplex operations. If the paired band is a TDD band, then a conjugate or inverse carrier may be used such that full duplex, or a close approximation thereto, is achieved. With the introduction of a paired channel and fast control channels, rapid uplink/downlink switching may be achieved for TDD carriers efficiently and effectively. Other aspects, embodiments, and features are also claimed and described.

PRIORITY CLAIM

This application claims priority to and the benefit of provisionalpatent application No. 62/000,454, titled “Apparatus and Method forInter-Band Pairing of Carriers for Time Division Duplex Transmit- andReceive-Switching and its Application to Multiplexing of DifferentTransmission Time Intervals” and filed in the U.S. Patent and TrademarkOffice on May 19, 2014, and provisional patent application No.62/000,443, titled “Apparatus and Method for Synchronous Multiplexingand Multiple Access for Different Latency Targets Utilizing ThinControl” and filed in the U.S. Patent and Trademark Office on May 19,2014, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to pairing inter-band timedivision duplex (TDD) carriers to achieve full duplex communication.

BACKGROUND

Wireless communication networks are widely deployed to provide variouscommunication services such as telephony, video, data, messaging,broadcasts, and so on. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources.

Within such wireless networks a variety of data services may beprovided, including voice, video, and emails. More recently, wirelesscommunication networks are being utilized for an even broader range ofservices, including mission critical applications and remote controlapplications such as tele-surgery, where real-time feedback isnecessary. In such applications, very low latency is critical to enablea suitably high quality of service. That is, the time for information tobe transmitted from a communication device, and a response received backat the communication device, may need to be extremely rapid, on theorder of milliseconds.

As the demand for mobile broadband access continues to increase,research and development continue to advance wireless communicationtechnologies not only to meet the growing demand for mobile broadbandaccess, but to advance and enhance the user experience.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a simplified summary of one or more aspects ofthe present disclosure, in order to provide a basic understanding ofsuch aspects. This summary is not an extensive overview of allcontemplated features of the disclosure, and is intended neither toidentify key or critical elements of all aspects of the disclosure norto delineate the scope of any or all aspects of the disclosure. Its solepurpose is to present some concepts of one or more aspects of thedisclosure in a simplified form as a prelude to the more detaileddescription that is presented later.

Various aspects of the present disclosure provide for the pairing of aninter-band carrier with a time division duplex (TDD) carrier. If thepaired band is a frequency division duplex (FDD) band, then basestations and mobile devices may transmit and receive additional thincontrol channels on FDD carriers to enable full duplex operations. Ifthe paired band is a TDD band, then a conjugate or inverse carrier maybe used such that full duplex, or a close approximation thereto, isachieved. With the introduction of a paired channel and fast controlchannels, rapid uplink/downlink switching may be achieved for TDDcarriers efficiently and effectively.

In one aspect, the disclosure provides a method, apparatus, andcomputer-readable medium having code for implementing wirelesscommunication utilizing an algorithm for pairing inter-band carriers fortime division duplex transmit- and receive switching. Here, asubordinate entity may wirelessly communicate with a scheduling entityutilizing a first transmission time interval (TTI) over a first carrier,the first carrier being a time division duplex (TDD) carrier. Further,the subordinate entity may wirelessly communicate utilizing a second TTIdifferent from the first TTI and at least partially overlapping thefirst TTI, over a second carrier paired with the first carrier butseparated from the first carrier in frequency.

These and other aspects of the invention will become more fullyunderstood upon a review of the detailed description, which follows.Other aspects, features, and embodiments of the present invention willbecome apparent to those of ordinary skill in the art, upon reviewingthe following description of specific, exemplary embodiments of thepresent invention in conjunction with the accompanying figures. Whilefeatures of the present invention may be discussed relative to certainembodiments and figures below, all embodiments of the present inventioncan include one or more of the advantageous features discussed herein.In other words, while one or more embodiments may be discussed as havingcertain advantageous features, one or more of such features may also beused in accordance with the various embodiments of the inventiondiscussed herein. In similar fashion, while exemplary embodiments may bediscussed below as device, system, or method embodiments it should beunderstood that such exemplary embodiments can be implemented in variousdevices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram conceptually illustrating an example of ascheduling entity communicating with one or more subordinate entitiesaccording to some embodiments.

FIG. 2 is a block diagram illustrating an example of a hardwareimplementation for a scheduling entity employing a processing systemaccording to some embodiments.

FIG. 3 is a block diagram illustrating an example of a hardwareimplementation for a subordinate entity employing a processing systemaccording to some embodiments.

FIG. 4 is a schematic diagram illustrating a synchronous multiple accesschannel structure in a full duplex system for multiplexing low latencyuplink data with regular uplink data according to one example.

FIG. 5 is a schematic diagram illustrating a synchronous multiple accesschannel structure with a time division duplex (TDD) carrier being pairedwith a frequency division duplex (FDD) carrier for multiplexing lowlatency uplink data with regular uplink data according to one example.

FIG. 6 is a call flow diagram illustrating an example of multiplexinglow latency uplink data with regular uplink data utilizing a thincontrol channel according to some embodiments.

FIG. 7 is a flow chart illustrating an example of multiplexing lowlatency uplink data with regular uplink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 8 is a schematic diagram illustrating a synchronous multiple accesschannel structure with a TDD carrier being paired with an FDD carrierfor multiplexing low latency downlink data with regular uplink dataaccording to one example.

FIG. 9 is a call flow diagram illustrating an example of multiplexinglow latency downlink data with regular uplink data utilizing a thincontrol channel according to some embodiments.

FIG. 10 is a flow chart illustrating an example of multiplexing lowlatency downlink data with regular uplink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 11 is a schematic diagram illustrating a synchronous multipleaccess channel structure with a TDD carrier being paired with an FDDcarrier for multiplexing low latency uplink data with regular downlinkdata according to one example.

FIG. 12 is a call flow diagram illustrating an example of multiplexinglow latency uplink data with regular downlink data utilizing a thincontrol channel according to some embodiments.

FIG. 13 is a flow chart illustrating an example of multiplexing lowlatency uplink data with regular downlink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 14 is a schematic diagram illustrating inverse (conjugate) pairingof time division duplex carriers according to one example.

FIG. 15 is a schematic diagram illustrating inverse (conjugate) pairingof time division duplex carriers according to another example.

FIG. 16 is a schematic diagram illustrating a synchronous multipleaccess channel structure with paired TDD carriers for multiplexing lowlatency uplink data with regular uplink data according to one example.

FIG. 17 is a call flow diagram illustrating an example of multiplexinglow latency uplink data with regular uplink data utilizing a thincontrol channel according to some embodiments.

FIG. 18 is a flow chart illustrating an example of multiplexing lowlatency uplink data with regular uplink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 19 is a schematic diagram illustrating a synchronous multipleaccess channel structure with paired TDD carriers for multiplexing lowlatency downlink data with regular uplink data according to one example.

FIG. 20 is a call flow diagram illustrating an example of multiplexinglow latency downlink data with regular uplink data utilizing a thincontrol channel according to some embodiments.

FIG. 21 is a flow chart illustrating an example of multiplexing lowlatency downlink data with regular uplink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 22 is a schematic diagram illustrating a synchronous multipleaccess channel structure with paired TDD carriers for multiplexing lowlatency uplink data with regular downlink data according to one example.

FIG. 23 is a call flow diagram illustrating an example of multiplexinglow latency uplink data with regular downlink data utilizing a thincontrol channel according to some embodiments.

FIG. 24 is a flow chart illustrating an example of multiplexing lowlatency uplink data with regular downlink data utilizing a thin controlchannel from the point of view of a scheduling entity, according to someembodiments.

FIG. 25 is a flow chart illustrating an example of wirelesscommunication utilizing a TDD carrier paired with a second carrier, andmultiplexing long and short TTIs, according to some embodiments.

FIG. 26 is a flow chart illustrating an example of wirelesscommunication utilizing a pair of TDD carriers for full duplexcommunication, according to some embodiments.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known structures and components areshown in block diagram form in order to avoid obscuring such concepts.

The various concepts presented throughout this disclosure may beimplemented across a broad variety of telecommunication systems, networkarchitectures, and communication standards. For example, the 3^(rd)Generation Partnership Project (3GPP) is a standards body that definesseveral wireless communication standards for networks involving theevolved packet system (EPS), frequently referred to as long-termevolution (LTE) networks. LTE networks can provide end-to-end latencybetween a transmitting device and a receiving device on the order of 50ms, with over-the-air latency for a particular packet being in the rangeof 10 ms. Currently known LTE functionality provides for a round triptime (RTT) for certain feedback signaling (i.e., hybrid automatic repeatrequest (HARQ) signaling) of at least about 8 ms, using a transmissiontime interval (TTI) of 1 ms. (Here, a TTI corresponds to a minimumduration of a unit of information that can be decoded.) For timedivision duplex (TDD) LTE configurations, the uplink/downlinkconfiguration has a relatively fixed configuration, which takes around10 ms to change. In general, LTE provides for a one-size-fits-allapproach, with all services and packets relying on these same latencyranges.

Evolved versions of the LTE network, such as a fifth-generation (5G)network, may provide for many different types of services orapplications, including but not limited to web browsing, videostreaming, VoIP, mission critical applications, multi-hop networks,remote operations with real-time feedback (e.g., tele-surgery), etc.Here, these different sets of services may benefit from having multiplelatency targets that are drastically different from one another.However, the one-size-fits-all aspects of the LTE network describedabove can make the multiplexing of traffic with different latencytargets very difficult.

The spectrum compatibility of a system that supports such diverselatency targets can be challenging. For example, the time multiplexingof regular/low latency traffic could violate the requirements of lowlatency packets. Furthermore, reserved frequency domain resources forlow latency traffic would limit the peak rate and trunking efficiency.Thus, for next generation networks there is a need for new ways tosupport the ability to multiplex various types, classes, and categoriestraffic and services, including but not limited to traffic havingdrastically different latency characteristics.

According to some aspects of the present disclosure, apparatus, methods,and computer instructions are disclosed, providing for the pairing of aninter-band carrier with a time division duplex (TDD) carrier. If thepaired band is a frequency division duplex (FDD) band, then basestations and mobile devices may transmit and receive additional thincontrol channels on FDD carriers to enable full duplex operations. Ifthe paired band is another TDD band, then a conjugate or inverse carriermay be used such that full duplex communication is achieved. With theintroduction of the paired channel and fast control channels, rapiduplink/downlink switching may be achieved for TDD carriers efficientlyand effectively, enabling the multiplexing of various types, classes,and categories of traffic and services.

Referring now to FIG. 1, a block diagram is provided illustrating ascheduling entity 102 and a plurality of subordinate entities 104engaged in wireless communication utilizing thin control channels108/112 and a thin feedback channel 114, described in further detailbelow. Of course, the channels illustrated in FIG. 1 are not necessarilyall of the channels that may be utilized between a scheduling entity 102and subordinate entities 104, and those of ordinary skill in the artwill recognize that other channels may be utilized in addition to thoseillustrated, such as other control and feedback channels. As illustratedin FIG. 1, the scheduling entity 102 may broadcast downlink data 106 toone or more subordinate entities 104. In accordance with aspects of thepresent disclosure, the term downlink may refer to a point-to-multipointtransmission originating at the scheduling entity 102. Broadly, thescheduling entity 102 is a node or device responsible for schedulingtraffic in a wireless communication network, including the downlinktransmissions and, in some examples, uplink data 110 from one or moresubordinate entities to the scheduling entity 102. (Another way todescribe the scheme may be to use the term broadcast channelmultiplexing.) In accordance with aspects of the present disclosure, theterm uplink may refer to a point-to-point transmission originating at asubordinate entity 104. Broadly, the subordinate entity 104 is a node ordevice that receives scheduling control information, including but notlimited to scheduling grants, synchronization or timing information, orother control information from another entity in the wirelesscommunication network such as the scheduling entity 102.

In a further aspect of the disclosure, the scheduling entity 102 maybroadcast a thin control channel 108 and/or 112 to one or moresubordinate entities 104. As described herein below, the use of a thincontrol channel 108/112 can enable modification/puncturing of uplinkand/or downlink data being transmitted using a first, long transmissiontime interval (TTI), with other data (e.g., low latency (LoLat) packets)utilizing a second, short TTI.

Furthermore, the subordinate entities 104 may transmit a thin feedbackchannel 114 to the scheduling entity 102. The thin feedback channel mayin some examples include a request for the scheduling entity tomodify/puncture a first, long TTI with LoLat packets utilizing a second,short TTI. Here, in response to the request transmitted on the thinfeedback channel 114, the scheduling entity 102 may transmit in the thincontrol channel 112 information that may schedulemodification/puncturing of the long, first TTI with LoLat packetsutilizing the second, short TTI.

FIG. 2 is a conceptual diagram illustrating an example of a hardwareimplementation for a scheduling entity 102 employing a processing system214. In accordance with various aspects of the disclosure, an element,or any portion of an element, or any combination of elements may beimplemented with a processing system 214 that includes one or moreprocessors 204.

In various aspects of the disclosure, the apparatus 200 may be anysuitable radio transceiver apparatus, and in some examples, may beembodied by a base station (BS), a base transceiver station (BTS), aradio base station, a radio transceiver, a transceiver function, a basicservice set (BSS), an extended service set (ESS), an access point (AP),a Node B, an eNode B (eNB), mesh node, relay, or some other suitableterminology. Within the present document, a base station may be referredto as a scheduling entity, indicating that the base station providesscheduling information to one or more subordinate entities.

In other examples, the apparatus 200 may be embodied by a wireless userequipment (UE). Examples of a UE include a cellular phone, a smartphone, a session initiation protocol (SIP) phone, a laptop, a notebook,a netbook, a smartbook, a personal digital assistant (PDA), a satelliteradio, a global positioning system (GPS) device, a multimedia device, avideo device, a digital audio player (e.g., MP3 player), a camera, agame console, an entertainment device, a vehicle component, a wearablecomputing device (e.g., a smart watch, a health or fitness tracker,etc.), an appliance, a sensor, a vending machine, or any other similarfunctioning device. The UE may also be referred to by those skilled inthe art as a mobile station (MS), a subscriber station, a mobile unit, asubscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal (AT), a mobile terminal, awireless terminal, a remote terminal, a handset, a terminal, a useragent, a mobile client, a client, or some other suitable terminology.Within the present document, a UE may be referred to either as ascheduling entity, or a subordinate entity. That is, in various aspectsof the present disclosure, a wireless UE may operate as a schedulingentity providing scheduling information to one or more subordinateentities, or may operate as a subordinate entity in accordance withscheduling information provided by a scheduling entity.

Examples of processors 204 include microprocessors, microcontrollers,digital signal processors (DSPs), field programmable gate arrays(FPGAs), programmable logic devices (PLDs), state machines, gated logic,discrete hardware circuits, and other suitable hardware configured toperform the various functionality described throughout this disclosure.That is, the processor 204, as utilized in an apparatus 200, may be usedto implement any one or more of the processes described below andillustrated in FIGS. 5-26.

In this example, the processing system 214 may be implemented with a busarchitecture, represented generally by the bus 202. The bus 202 mayinclude any number of interconnecting buses and bridges depending on thespecific application of the processing system 214 and the overall designconstraints. The bus 202 links together various circuits including oneor more processors (represented generally by the processor 204), amemory 205, and computer-readable media (represented generally by thecomputer-readable medium 206). The bus 202 may also link various othercircuits such as timing sources, peripherals, voltage regulators, andpower management circuits, which are well known in the art, andtherefore, will not be described any further. A bus interface 208provides an interface between the bus 202 and a transceiver 210. Thetransceiver 210 provides a means for communicating with various otherapparatus over a transmission medium. Depending upon the nature of theapparatus, a user interface 212 (e.g., keypad, display, speaker,microphone, joystick) may also be provided.

In some aspects of the disclosure, the processor 204 may includeresource assignment and TTI control circuitry 241, configured togenerate, schedule, and modify a resource assignment or grant oftime-frequency resources. The resource assignment and TTI controlcircuitry 241 may further be configured to determine the TTI to utilizefor uplink and downlink transmissions, e.g., whether data transmissionsshould utilize a first, long TTI, or a second, short TTI. The resourceassignment and TTI control circuitry 241 may operate in coordinationwith resource assignment and TTI control software 251. The processor 204may further include data and control channel generation and transmissioncircuitry 242, configured to generate and transmit uplink and downlinkdata and control channels, as well as uplink feedback channels anddownlink control channels, including but not limited to a thin controlchannel, a thin feedback channel, a LoLat grant channel, a grantmodification channel, and an assignment channel. The data and controlchannel generation and transmission circuitry 242 may operate incoordination with data and control channel generation and transmissionsoftware 252. The processor 204 may further include thin feedbackreception and processing circuitry 243, configured to receive schedulingrequests on an uplink feedback channel, the scheduling requests beingconfigured to request a grant of time-frequency resources for uplinkuser data transmissions. The thin feedback reception and processingcircuitry 243 may operate in coordination with thin feedback receptionand processing software 253. The processor 204 may further include datachannel reception and processing circuitry 244, configured to receiveand process user data on uplink data channels from one or moresubordinate entities. The data channel reception and processingcircuitry 244 may operate in coordination with data channel andreception and processing software 254. The processor 204 may furtherinclude TDD control circuitry 245 and FDD control circuitry 246,configured to control wireless communication (e.g., transmission and/orreception of data and/or control channels) on one or more TDD or FDDcarriers, respectively. The TDD control circuitry may operate incoordination with TDD control software 255. The FDD control circuitrymay operate in coordination with FDD control software 256.

The processor 204 is responsible for managing the bus 202 and generalprocessing, including the execution of software stored on thecomputer-readable medium 206. The software, when executed by theprocessor 204, causes the processing system 214 to perform the variousfunctions described below for any particular apparatus. Thecomputer-readable medium 206 may also be used for storing data that ismanipulated by the processor 204 when executing software.

One or more processors 204 in the processing system may executesoftware. Software shall be construed broadly to mean instructions,instruction sets, code, code segments, program code, programs,subprograms, software modules, applications, software applications,software packages, routines, subroutines, objects, executables, threadsof execution, procedures, functions, etc., whether referred to assoftware, firmware, middleware, microcode, hardware descriptionlanguage, or otherwise. The software may reside on a computer-readablemedium 206. The computer-readable medium 206 may be a non-transitorycomputer-readable medium. A non-transitory computer-readable mediumincludes, by way of example, a magnetic storage device (e.g., hard disk,floppy disk, magnetic strip), an optical disk (e.g., a compact disc (CD)or a digital versatile disc (DVD)), a smart card, a flash memory device(e.g., a card, a stick, or a key drive), a random access memory (RAM), aread only memory (ROM), a programmable ROM (PROM), an erasable PROM(EPROM), an electrically erasable PROM (EEPROM), a register, a removabledisk, and any other suitable medium for storing software and/orinstructions that may be accessed and read by a computer. Thecomputer-readable medium may also include, by way of example, a carrierwave, a transmission line, and any other suitable medium fortransmitting software and/or instructions that may be accessed and readby a computer. The computer-readable medium 206 may reside in theprocessing system 214, external to the processing system 214, ordistributed across multiple entities including the processing system214. The computer-readable medium 206 may be embodied in a computerprogram product. By way of example, a computer program product mayinclude a computer-readable medium in packaging materials. Those skilledin the art will recognize how best to implement the describedfunctionality presented throughout this disclosure depending on theparticular application and the overall design constraints imposed on theoverall system.

FIG. 3 is a conceptual diagram illustrating an example of a hardwareimplementation for an exemplary subordinate entity 104 employing aprocessing system 314. In accordance with various aspects of thedisclosure, an element, or any portion of an element, or any combinationof elements may be implemented with a processing system 414 thatincludes one or more processors 304.

The processing system 314 may be substantially the same as theprocessing system 214 illustrated in FIG. 2, including a bus interface308, a bus 302, memory 305, a processor 304, and a computer-readablemedium 306. Furthermore, the subordinate entity 304 may include a userinterface 312 and a transceiver 310 substantially similar to thosedescribed above in FIG. 2. The processor 304, as utilized in asubordinate entity 104, may be used to implement any one or more of theprocesses described below and illustrated in FIGS. 5-26.

In some aspects of the disclosure, the processor 304 may include fastsuspension of uplink transmissions circuitry 341, configured for quicklysuspending uplink transmissions, e.g., by driving a zero input to apower amplifier within the transceiver 310, or in another example, beingcapable of quickly turning off the power amplifier in the transceiver310. The fast suspension of uplink transmissions circuitry 341 mayoperate in coordination with fast suspension of uplink transmissionssoftware 351. The processor 304 may further include data and controlchannel generation and transmission circuitry 342, configured togenerate and transmit uplink data on a data channel, and to generate andtransmit uplink control information and feedback information on controland feedback channels. The data and control channel generation andtransmission circuitry 342 may operate in coordination with data andcontrol channel generation and transmission software 352. The processor304 may further include data and control channel reception andprocessing circuitry 343, configured for receiving and processingdownlink data on a data channel, and to receive and process controlinformation on one or more downlink control channels. In some examples,received downlink data and/or control information may be temporarilystored in a data buffer within memory 305. The data and control channelreception and processing circuitry 343 may operate in coordination withdata and control channel reception and processing software 353. Theprocessor 304 may further include TDD control circuitry 344 and FDDcontrol circuitry 345, configured to control wireless communication(e.g., transmission and/or reception of data and/or control channels) onone or more TDD or FDD carriers, respectively. The TDD control circuitrymay operate in coordination with TDD control software 354. The FDDcontrol circuitry may operate in coordination with FDD control software355.

As described below, some aspects of the disclosure provide for wirelesscommunication utilizing a TDD carrier paired with a second carrier, andmultiplexing long and short TTIs on the paired carriers. Further aspectsof the disclosure provide for wireless communication utilizing a pair ofTDD carriers for full duplex communication.

Of course, these examples are merely provided to illustrate certainconcepts of the invention. Those of ordinary skill in the art willcomprehend that these are merely exemplary in nature, and other examplesmay fall within the scope of the disclosure and the appended claims.

Thin Control Channel in a Full Duplex System

Some aspects of the present disclosure provide for synchronousmultiplexing of different classes of services and traffic havingdifferent latency targets. For example, multiplexing may be enabled byutilizing a certain “thin control channel,” described below. This thincontrol channel may provide for fast signaling to enable themultiplexing of data with short TTIs and other data with long TTIs. Asone example, high priority, low latency (LoLat) data having a short TTImay be enabled to interrupt regular traffic having a long TTI. FIG. 4 isa schematic diagram illustrating an example of a synchronous multipleaccess channel structure including a “thin” control channel as it may beimplemented according to some aspects of the present disclosure. Asillustrated in FIG. 4, the channel structure may be applicable to anuplink data transmission, i.e., a transmission from a subordinate entity104 to a scheduling entity 102. Of course, this channel structure is notlimited to such a scheme, but rather may be generalized to be applicableto any link where the receiving device is scheduling the traffic.

In the illustration, the horizontal axis (t) represents time, while thevertical axis (f) generally represents frequency (not to scale). Channelresources for various users of the air interface occupy given areaswithin the channel, as outlined in the different blocks. For example,some of the time-frequency resources may be utilized by “regular” users402, which have less stringent latency requirements for theircommunication. In the illustration, as one example, six regular users402 labeled User A, B, C, D, E, and F are each scheduled time-frequencyresources as indicated by their respectfully labeled blocks. Of course,in various examples any number of users may be scheduled the use ofresources. Further, while in the illustration all of the time-frequencyresources are shown being assigned to regular users, in various examplessome or even all of the time-frequency resources may be unassigned, orassigned for another purpose other than for regular user data.

In the context of the present disclosure, a regular user 402 may be asubordinate entity 104 that receives a resource assignment from ascheduling entity 102, where the resource assignment indicates for thesubordinate entity 104 to utilize a long transmission time interval(TTI). Such regular users 402 may be more tolerant to latency in theircommunication, and may in some examples be more optimized for capacity.Accordingly, these users may utilize such longer TTIs for packets thatcan tolerate more latency than other users or other types ofcommunication that might require low latency (LoLat) communication. Along TTI may broadly be any TTI that is longer than a short TTI,described in further detail below. In some examples, a long TTI may be aTTI that has a duration of a plurality of data symbols, or time slots.Some non-limiting examples of a long TTI may have a duration of 100 μs,240 μs, or 1 ms. Of course, any suitable duration for a long TTI may beutilized within the scope of the disclosure.

Furthermore, as illustrated in FIG. 4, in addition to the uplink datatraffic channels used by the regular users 402, a “thin” feedbackchannel 407 in the uplink direction may be utilized as illustrated.Here, the thin feedback channel 407 may be the same as the thin feedbackchannel 114 described above and illustrated in FIG. 1. Within thepresent disclosure, the thin feedback channel may lie in one or morefrequency sub-band(s) outside of (e.g., above) the frequency sub-bandsutilized by the uplink traffic transmissions, such as the allocatedtime-frequency resources described above for regular users A-F 402. Thewidth of the thin feedback channel 407 in the frequency direction may bereduced or minimized so as to reduce or minimize the amount of overheadutilized by the thin feedback channel 407.

Still further, as illustrated in FIG. 4, in addition to the uplinktraffic and feedback channels, a thin control channel 406 may beutilized in the downlink direction as illustrated. Here, the thincontrol channel 406 may be the same as one or both of the thin controlchannels 108/112 described above and illustrated in FIG. 1. Within thepresent disclosure, the thin control channel may lie in one or morefrequency sub-band(s) outside of the frequency sub-bands utilized by theuplink traffic and feedback transmissions, such as the allocatedtime-frequency resources described above for regular users A-F 402 andthe thin feedback channel 407. For example, in a frequency divisionduplex (FDD) system, the thin control channel 406 may be in a differentband than the uplink traffic and feedback channels. The width of thethin control channel 406 in the frequency direction may be reduced orminimized so as to reduce or minimize the amount of overhead utilized bythe control channel 406. In a further aspect, all active users (e.g.,subordinate entities 104 including but not necessarily limited to theregular users 402) in communication with the scheduling entity 102 thatbroadcasts the thin control channel 406 may monitor (and, in someexamples, buffer) the thin control channel 406 shown herein.

As illustrated in FIG. 4, each time slot, symbol, or unit of the thincontrol channel 406 may correspond to the duration of a short TTI. Thatis, in some examples, the short TTI may correspond to the time durationof a single symbol. Some non-limiting examples of a short TTI may have aduration of 10 μs, 20 μs, 100 μs, or any other suitable duration that isshorter than the long TTI. In some examples, the long TTI may representan integer multiple of short TTIs. In some examples, a common symbolduration may be utilized within both the long TTI and the short TTI, orin other examples, different symbol durations may be utilized within thelong TTI and the short TTI. The duration of information symbols carriedwithin either of the long or short TTIs may also take any suitableduration, with one example being a 10 μs duration for each symbol. In anexample wherein orthogonal frequency division multiplexing is adopted,an additional 1 μs cyclic prefix may be added to the symbol duration.

In an aspect of the present disclosure, this thin control channel 406can enable dynamic multiplexing of the traffic for the LoLat users 404,who utilize the short TTI, and the traffic for the regular users 402,who utilize the long TTI. That is, a plurality of regular users 402 maybe transmitting uplink communications utilizing an existing assignmentof time-frequency resources. Here, any suitable control channel,including but not necessarily limited to the thin control channel 406,may be utilized to grant resources to the various entities in thenetwork, such that those subordinate entities 104 may transmit uplinkdata according to their respective assignments utilizing the long TTI.

Here, it may be the case that a subordinate entity in the network wishesto transmit LoLat data. Here, in order to maintain orthogonality among aplurality of subordinate entities, a central, scheduling entity may beutilized to schedule the uplink transmissions by each of the subordinateentities, and they may generally not randomly transmit uplink datawithout receiving assigned time-frequency resources for suchtransmission. Accordingly, when a subordinate entity determines that ithas traffic (e.g., high priority traffic) that it wishes to betransmitted with a lower latency, then the subordinate entity maytransmit a LoLat scheduling request 409 on the thin feedback channel407. The LoLat scheduling request 409 is illustrated as occupying asingle short TTI, although this is not necessarily always the case, andvarious LoLat scheduling requests might occupy any suitable number ofshort TTIs or symbol lengths. The contents of the LoLat schedulingrequest 409 may include information about the LoLat data that thetransmitting entity wishes to transmit, such as, for example, length,data type, priority, latency, or any other suitable information relatingto the LoLat data.

In response to the LoLat scheduling request 409, the receiving end ofthe LoLat scheduling request 409 (e.g., the scheduling entity) mayaccordingly determine to grant a scheduling adjustment. In this way, thescheduling entity may make resources available for the requestingsubordinate entity to make its LoLat transmission. Thus, the schedulingentity may transmit, on the thin control channel 406, an uplink grantmodification 408 to its regular users 402. The uplink grant modification408 may notify the regular users 402 that their grant is being modified,and that the previously allocated long TTI time-frequency resources willbe punctured, and that the resources will not be used by the regularusers 402. Here, puncturing the resources of the regular user 402 may insome examples mean that the regular user 402 ceases transmitting duringthe time associated with the re-assigned short TTI. In other examples,where one or more means of channel multiplexing may be used (includingbut not limited to frequency division multiplexing and code divisionmultiplexing), puncturing the resources of the regular user 402 may meanthat the regular user 402 ceases using punctured resources but maycontinue transmitting uplink data utilizing another frequency or anotherscrambling code, other than the resource granted to the LoLat user 404,in order to maintain orthogonality. As described above, the thin controlchannel 406 may be a point-to-multipoint broadcast channel monitored byall subordinate entities in communication with the scheduling entity. Inthis way, any user or users having their formerly granted time-frequencyresources punctured by the uplink grant modification 408 can be informedor instructed not to transmit their uplink transmission utilizing theparticular time-frequency resource now allocated to a LoLat user 404.

In a further aspect, the uplink grant modification 408 may not onlyinclude grant modification information directed to the regular users402, but in some examples may further include grant information directedto the requesting LoLat user 404 indicating that the puncturedtime-frequency resources have been allocated to the LoLat user 404. Inanother example within the scope of the present disclosure, the grantinformation directed to the requesting LoLat user 404 may be carried ona separate uplink grant channel (not illustrated). That is, the thincontrol channel may in some examples exclude grant information for theLoLat user 404, this information being transmitted on any suitabledownlink channel readable by the requesting LoLat user 404. In any case,grant information directed to the requesting LoLat user 404 may includeinformation identifying the LoLat user 404, identifying one or moretime-frequency resources, modulation and coding schemes, transmissionschemes, or any other suitable information relating to the grantedresource for the requesting LoLat user 404.

In the illustration of FIG. 10, the LoLat user 404 transmits the LoLatscheduling request 409, but all subordinate entities, including theregular users 402, receive the uplink grant modification 408. Here, in afurther aspect of the disclosure, the regular users 402 may beconfigured such that they are capable of decoding the uplink grantmodification 408 relatively quickly, so that they can promptly ceasetransmitting (e.g., puncture their transmissions) during there-allocated short TTI(s). In this way, the time-frequency resources mayquickly be made available for the LoLat user 404 to transmit its LoLatsymbols.

The illustrated example of FIG. 4 applies to a full-duplex scheme,wherein downlink channels such as the thin control channel 406 may beutilized at the same time as uplink channels such as the uplink datachannels. In this scheme, because communication in both directionssimultaneously is enabled, all of the active users may monitor (and, insome examples, buffer) the thin control channel 406 shown herein.However, in a half-duplex scheme, such as a time division duplex (TDD)channel structure, multiplexing of data having different TTIsnecessitates additional considerations.

Thin Control Channels in a TDD System—Paired Carriers

Thin control channels such as the thin control channel 406 describedabove have been identified as an enabling feature for many potentialuses. For example, by utilizing a thin control channel, a communicationsystem can be provided with low-latency data rate control, coordinatedmulti-point (CoMP) solutions, and improved access to unlicensed bands.Of course, these are merely some examples of features that may beenabled with the use of a thin control channel, and those of ordinaryskill in the art will comprehend that other features may be enabled byway of the thin control channel. One relevant feature provided by theuse of the thin control channel is opportunistic transmission/receptionswitching, wherein the thin control channel in one direction may beutilized to rapidly modify data communication in the other direction.

Time division duplexing (TDD) is a well-known duplexing technique thatprovides for two-way communication between devices by applying timedivision multiplexing to separate the signals going in differentdirections from one another. As an example, channel resources may bedivided into time slots, where some of the time slots are allocated foruplink transmissions, and other time slots are allocated for downlinktransmissions. In this TDD scheme, only uplink or downlinktransmissions, and not both, may take place during any particular timeslot within that TDD band. One drawback of the TDD scheme is that it isonly a half-duplex scheme, because only one direction of communicationis possible at any given instant. Because of its half-duplex nature,opportunistic transmission/reception switching with a fast controlchannel during the middle of an ongoing transmission/reception, asdescribed above in relation to FIG. 4 with the introduction of a thincontrol channel, is in general not possible. That is, referring again toFIG. 4, if a particular user (e.g., User D) is transmitting its uplinkat the time when the uplink grant modification 408 is transmitted, thisuser would not receive the uplink grant modification 408, and thus,would not be informed of the grant modification, prohibiting thepuncturing of its uplink transmission to make room for the LoLat user404.

One exception, wherein TDD alone may be sufficient, may be in the caseof the multiplexing of resources with different TTIs on downlinkcommunications (e.g., downlink/downlink multiplexing, where one downlinktransmission of a first TTI may be interrupted by another downlinktransmission of a second TTI), which can be achieved without full duplexoperation. That is, in this case, the transmission of a thin controlchannel and a data channel would be in the same downlink direction, andthus, the transmitter could continue transmitting, and the receivercould continue receiving, in a one-direction (or half-duplex)configuration.

Therefore, to provide for improved functionality from a thin controlchannel in the case of uplink/uplink multiplexing, downlink/uplinkmultiplexing, or uplink/downlink multiplexing, the enablement of fullduplex operation and functionality, even on a TDD spectrum, would bedesirable.

Referring again to FIG. 4, this example of thin control for uplink data(i.e., transmissions from a subordinate entity) includes bi-directionalfull duplex communication, including regular user data 402 and a thinfeedback channel 407 in the uplink direction, as well as a thin controlchannel 406 in the downlink direction. Here, it can be seen that thethin control channel 406 may transmit during each short TTI, and inaddition, if a transmitting device (e.g., subordinate entity) wishes tointerrupt and transmit LoLat data 404, then at the same time as one ofthe thin control channel transmissions in the downlink direction, theLoLat user 404 may transmit in the uplink direction a LoLat schedulingrequest 409. (Additionally, the inserted LoLat packets may be downlinkpackets, or any other variation from the uplink packets that wereinterrupted).

In a strict TDD system, this scheme would not be possible, because thedevice could not autonomously (without informing the other side of thelink) interrupt transmissions in one direction with transmissions in theother direction. Similarly, if the UE is undertaking uplinktransmissions, if it is a strict TDD system, the UE would not be awareof any attempt by the receiving device to modify the grant, becausewhile transmitting the uplink it would not be receiving anything on thedownlink at all.

Therefore, in accordance with some aspects of the present disclosure, achannel structure is provided that incorporates a pairing of a TDDcarrier with a second carrier, wherein the TDD carrier and the secondcarrier may be in different bands from one another (inter-bandcarriers). When the paired carrier provides an inverse, conjugate, orcomplementary direction of communication as that of the TDD carrier,full-duplex communication can be achieved, at least in some of the timeslots, by simultaneous utilization of an uplink direction ofcommunication in one carrier and a downlink direction of communicationin the other carrier.

In some examples, the paired (second) carrier may be in a frequencydivision duplex (FDD) band, which is capable of full duplexcommunication. That is, if the paired carrier is an FDD carrier, thepaired carrier can include a plurality of carriers, such as an uplinkcomponent carrier and a downlink component carrier. Accordingly, if thepaired carrier is in an FDD band, then both ends of the link (schedulingand subordinate) can simultaneously transmit and receive a thin controlchannel on the FDD carrier.

In other examples, the paired carrier may be in a TDD band. In thiscase, in an aspect of the present disclosure, the two paired TDDcarriers may implement conjugate or inverse duplexing, such that fullduplex is achieved. This conjugate duplexing generally establishes thatduring some or all of the time slots or frames in one of the carriers,when those frames are configured for communication in one direction,then at that same time, a corresponding time slot or frame in the pairedcarrier is configured for communication in the other direction. In thisway, by implementing paired carriers and fast (thin) control channels,among other functions, rapid uplink/downlink switching and multiplexingcan be achieved for TDD carriers in an efficient and effective manner.

Downlink/Downlink Multiplexing

In an aspect of the disclosure, described above, downlink/downlinkmultiplexing (e.g., enabling fast and dynamic switching between long andshort TTIs) for data transmitted on a TDD carrier, need not necessarilyutilize paired carriers. That is, because a thin control channel may becarried in the same direction, and at the same time as the downlink dataon a TDD carrier, dynamic switching of TTIs can be accomplished on thefly by the scheduling entity that is transmitting the downlink utilizinga single TDD carrier.

FDD-TDD Carrier Pairing

In some aspects of the disclosure, a TDD carrier may be paired with asecond carrier that lies in a frequency division duplex (FDD) band,wherein the FDD carrier may include paired uplink and downlink componentcarriers that provide for full duplex communication in the FDD band. Asdescribed in further detail below, with this pairing, dynamicuplink/downlink switching can be achieved on data channels on the TDDcarrier with the help of control channels on the FDD carrier.

FDD-TDD Carrier Pairing: Multiplexing LoLat UL on a Regular UL

FIG. 5 illustrates one example of pairing a TDD carrier with an FDDcarrier, providing for multiplexing of LoLat uplink transmissions withregular uplink transmissions (i.e., transmissions from a subordinateentity) on the TDD carrier. In the illustrated example, the TDD carrieris illustrated in much the same way as the TDD carrier in FIG. 4, withuplink resources allocated to different users being represented by thelarge blocks spanning a long TTI. Here, as will be described in furtherdetail below, a subordinate entity (e.g., a UE) may request, and begranted, resources for a LoLat transmission that may be multiplexed withthe “regular” uplink transmissions from other users. At the top of thefigure, resources on an FDD band are allocated, including an uplinkcomponent carrier and a downlink component carrier.

In the illustrated example, control channels for controlling the TDDuplink data are carried on the FDD component carriers. That is, the FDDband includes in its uplink component carrier a thin feedback channel506 that a subordinate entity can utilize to transmit information suchas a low latency (LoLat) scheduling request 507. The FDD band furtherincludes, in its downlink component carrier, a thin control channel 508,which may carry uplink grant modification information 509 that modifiesan uplink resource grant corresponding to the subordinate entity uplinktransmission on the TDD carrier. Still further, the FDD band includes,in its downlink component carrier, a LoLat grant channel 510, which maycarry grant information 511 for the subordinate entity that requestedLoLat scheduling to utilize in a LoLat uplink transmission on the TDDcarrier.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for uplink transmissions onthe TDD carrier to one or more subordinate entities (e.g., Users A-F) byutilizing any suitable downlink grant channel (not necessarily one ofthe illustrated channels). As these uplink transmissions are ongoing, ifa particular subordinate entity, denoted as the LoLat user 504, wishesto request resources for a LoLat uplink transmission, this subordinateentity may transmit a LoLat scheduling request 507 on the thin feedbackchannel 506 on the FDD uplink component carrier. Here, the LoLatscheduling request 507 may utilize the short TTI, although this is notnecessarily always the case. In response, if the scheduling entitywishes to grant the requested LoLat resource, the scheduling entity 102may transmit, on the FDD downlink component carrier, an uplink grantmodification 509 on the thin control channel 508, and a LoLat grant 511on the LoLat grant channel 511. Here, the an uplink grant modification509 on the thin control channel 508 may be configured to inform all ofthe subordinate entities that are utilizing an existing grant of uplinktime-frequency resources that some or all of their granted resources arebeing modified or removed, to make way for the LoLat transmission.Further, the LoLat grant 511 on the LoLat grant channel 510 may beconfigured to inform the subordinate entity that transmitted the LoLatscheduling request (i.e., the LoLat user 504) of its grantedtime-frequency resources. In the illustration, the LoLat grant 511 isshown as occupying a wider bandwidth than the UL grant modification 509.This represents that, while the UL grant modification 509 may simply bea few bits representing the frequency resources that are beingre-allocated away from a regular user 502, and a number of short TTIs,the LoLat grant 511 may include more precise information relating to theLoLat resource assignment such as a user ID, the assignment information,a modulation and coding scheme, etc. Accordingly, the LoLat user 504 maytransmit its LoLat uplink transmission on the TDD carrier, while other“regular” users 502 (such as Users D, E, and F) may cease their uplinktransmissions, resulting in an orthogonal multiple access scheme betweenregular and LoLat uplink transmissions on the TDD carrier.

In this example, the regular users 502 (e.g., subordinate entities 104),whose uplink resources were punctured, may benefit from having anability to quickly decode the uplink grant modification 509. That is,the time from when the uplink grant modification 509 is received at theregular user 502, until that user ceases its uplink transmissions, maybe very short. To accommodate the quick reaction time, the subordinateentity 104 may be configured for a fast suspension of its uplinktransmissions, e.g., by driving a zero input to a power amplifier withinthe transceiver 310, or in another example, being capable of quicklyturning off the power amplifier. Furthermore, the LoLat user 504 alsomay have only a brief time from the receiving of its LoLat uplink grant511, and its transmission of LoLat uplink data. Accordingly, fastprocessing of the LoLat grant 511 and transmission utilizing thescheduled time-frequency resources would be beneficial and reducelatency.

FIG. 6 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink data with different latencytargets utilizing a TDD data carrier paired with FDD component carriersfor control information. In this illustration, time moves forward in thedownward direction, and communication signals between the illustratedentities are denoted with arrows between the lines below the respectiveentities. As illustrated, a scheduling entity 501 is in communicationwith a plurality of subordinate entities 104, including a regular user502 and a LoLat user 504. Each entity 501, 502, and 504 is configuredfor communication over a TDD carrier, and an FDD carrier. The respectiveTDD and FDD carriers are illustrated schematically with the two verticallines extending down from each respective entity.

FIG. 6 is described below in conjunction with a flow chart illustratedin FIG. 7. That is, FIG. 7 is a flow chart illustrating an exemplaryprocess 700 for resource assignment and re-assignment in accordance withsome aspects of the present disclosure. The process 700 is describedfrom the point-of-view of a scheduling entity 501, and may accordingly,as described in conjunction with FIG. 6, be operational at thescheduling entity 102 described above in conjunction with FIGS. 1 and/or2. In other examples within the scope of the present disclosure, theprocess 700 may be operational by a general purpose processor, aprocessing system 214 as described above and illustrated in FIG. 2, orany suitable means for carrying out the described functions. Thespecific order of steps or blocks shown in FIG. 7 is merely exemplary innature, and in various aspects of the disclosure, these steps or blocksmay occur in any suitable order, with some examples including two ormore steps or blocks occurring simultaneously.

At block 702, the scheduling entity 501 may transmit a first assignmentor grant 510 of time-frequency resources to at least one subordinateentity on the FDD downlink component carrier. Any suitable controlchannel on the FDD downlink component carrier may be utilized for thefirst resource assignment, such as a downlink assignment channel. Here,the first resource assignment 510 may be configured to indicate whichtime-frequency resource or resources are assigned to the respectivesubordinate entities for regular transmissions of uplink data, that is,transmissions utilizing the long TTI. In accordance with the firstresource assignment 510, at block 704, the scheduling entity 501 mayreceive regular uplink data 512 on the TDD uplink carrier from the atleast one subordinate entity (e.g., the subordinate entities 502 and504) utilizing the long TTI. Here, with reference to FIG. 5, thisregular uplink data 512 may correspond to the transmissions from regularusers 502. As illustrated in FIG. 6 with the dashed-line arrow, regularuplink data may optionally be transmitted from the second subordinateentity 504, depending on the contents of the first resource assignment510 and whether the second subordinate entity 504 is configured totransmit uplink data transmissions utilizing the long TTI.

The blocks 702 and 704 may repeat, or be iterated a plurality of timesin various examples, as regular uplink data 512 may continue to betransmitted from the subordinate entities. However, at any given time,it may arise that the subordinate entity 504 (i.e., the LoLat user 504)may wish to transmit LoLat data to the scheduling entity 501.Accordingly, at block 706, the scheduling entity 501 may receive a LoLatscheduling request 507 on the thin feedback channel 506 on the FDDuplink component carrier from the LoLat user 504 (i.e., the secondsubordinate entity 504). The LoLat scheduling request 507 may includeinformation identifying the requesting subordinate entity 504, andincluding any pertinent information relating to the LoLat data desiredto be transmitted.

At block 708, the scheduling entity 501 may transmit an uplinkscheduling grant modification 509 on the thin control channel 508 on theFDD downlink component carrier. Here, the uplink scheduling grantmodification 509 may instruct the regular users such as the firstsubordinate entity 502, having granted time-frequency resources forlong-TTI uplink transmissions, to puncture their uplink transmissionsduring at least one designated short TTI. Further at block 710, thescheduling entity 501 may transmit a second resource assignment or grant511 of time-frequency resources to the requesting subordinate entity(i.e., the LoLat user 504) on the LoLat grant channel 510 on the FDDdownlink component carrier. Here, the second resource assignment 511 mayinclude information identifying the requesting subordinate entity 504,and information identifying time-frequency resources granted on the TDDuplink carrier for the LoLat uplink transmission. In some examples, thetransmission of the uplink scheduling grant modification 509 at block708, and the transmission of the second resource assignment 511 at block710, may occur simultaneously. That is, these transmissions may bemultiplexed, for example, utilizing different time-frequency resources.In other examples, these transmissions may be at different times,according to the details of a particular implementation.

Block 712 represents operations at one or more subordinate entities,such as regular users 502 and LoLat user(s) 504. That is, in response tothe uplink grant modification 509, the regular users (i.e., the firstsubordinate entity 502) may puncture their previously scheduled uplinkdata transmissions that utilize the long TTI. Further, in response tothe second resource assignment 511, the LoLat user(s) (i.e., the secondsubordinate entity 504) may transmit the LoLat uplink data 514 utilizingthe assigned time-frequency resources on the TDD carrier.

At block 714, the scheduling entity 501 may receive the LoLat uplinkdata 514 transmitted from the requesting subordinate entity 504utilizing the short TTI on the TDD carrier.

Block 716 represents operations at one or more subordinate entities,such as the regular users 502 and, in some examples, LoLat user(s) 504.That is, the regular subordinate entities may resume their regularuplink data transmissions on the TDD uplink carrier when transmission ofthe LoLat uplink data has been completed. Accordingly, at block 718, thescheduling entity 502 may resume receiving regular uplink data on theTDD uplink carrier from one or more subordinate entities utilizing thelong TTI.

By utilizing the above scheme, pairing a TDD carrier for uplink datatransmissions with FDD carriers for control channel transmissions, athin control channel 508 can enable a scheduling entity to multiplex atleast two different data types or categories, having different TTIs, foruplink transmissions from a set of subordinate entities.

FDD-TDD Carrier Pairing: Multiplexing LoLat DL on Regular UL

FIG. 8 illustrates another example of pairing a TDD carrier with an FDDcarrier, providing for multiplexing of LoLat downlink transmissions(i.e., transmissions from a scheduling entity) with regular uplinktransmissions (i.e., transmissions from a subordinate entity) on the TDDcarrier. In the illustrated example, the TDD carrier is illustrated inmuch the same way as the TDD carrier in FIG. 4, with uplink resourcesshown with a plurality of users (subordinate entities) transmitting“regular” uplink data utilizing a long TTI. Here, as will be describedin further detail below, the scheduling entity may modify the schedulingassignment or grant of time-frequency resources, interrupting theongoing uplink transmissions on the TDD carrier, with downlinktransmissions on the TDD carrier.

In the illustrated example, a control channel for controlling the userdata carried on the TDD carrier is carried on an FDD downlink componentcarrier. That is, the FDD band includes in its downlink componentcarrier a LoLat grant channel 808, in which a subordinate entity mayreceive information such as a LoLat downlink grant 810.

In this example, because an FDD carrier is paired with the TDD carrier,the subordinate entity may always be receiving a control channel in thedownlink direction on the FDD carrier, even while uplink transmissionsare ongoing on the TDD carrier. Furthermore, in an aspect of thedisclosure, if a particular subordinate entity is not currentlytransmitting uplink data on the TDD carrier, then that particular usermay be configured always to listen for downlink data on the TDD carrier.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for uplink transmissions onthe TDD carrier to one or more subordinate entities (e.g., Users A-F) byutilizing any suitable downlink grant channel (not necessarily one ofthe illustrated channels).

At any given time, during the regular users' 802 transmission of theuplink data on the TDD carrier, the scheduling entity may determine totransmit LoLat downlink data on the TDD carrier. That is, at any time,one or more subordinate entities in communication with the schedulingentity, such as a LoLat user 804, may come to need LoLat communicationwith the network, wherein more stringent latency requirements forcommunication are needed than the relatively long latency resulting fromthe communication by regular users utilizing the long TTI. Thus, in anaspect of the present disclosure, the availability of the LoLat grantchannel 808 on the FDD downlink component carrier may enable dynamicmultiplexing of the traffic for one or more subordinate entities thatdesire low latency communication (hereinafter referred to as LoLat users804), who can utilize a short TTI for data traffic, and the traffic forthe regular users 802, who utilize the long TTI for data traffic.

Accordingly, on the LoLat grant channel 808 on the FDD downlinkcomponent carrier, at any given time, the scheduling entity maybroadcast a LoLat downlink grant 810. The LoLat downlink grant 810 maybe structured in any suitable manner. As one example, the LoLat downlinkgrant 810 may include information to identify one or more LoLat usersfor which LoLat downlink data is being granted, information identifyingtime-frequency resources being allocated to the user, and any othersuitable information regarding receiving and decoding of the downlinkdata.

At the same time, on the TDD carrier, the scheduling entity maybroadcast LoLat downlink data to the LoLat user(s) 804, in accordancewith the LoLat downlink grant 810. That is, in some examples, the LoLatdownlink grant 810 and the LoLat downlink data may be transmitted at thesame time, i.e., during the same short TTI. However, this is notnecessarily the case, and in other examples, the LoLat downlink grant810 and the LoLat downlink data may be transmitted during completelynon-overlapping short TTIs, or, as illustrated in FIG. 8, a single shortTTI may be utilized for the LoLat downlink grant 810, which may overlapwith any number (including zero) of short TTIs during which the LoLatdownlink data is transmitted on the TDD carrier.

That is, the LoLat user 804 (i.e., the subordinate entity addressed inthe LoLat grant 810) may be configured to receive and buffer the frameon the TDD carrier, even if it is not actively receiving the regulardownlink data on the TDD carrier. Upon processing the LoLat downlinkgrant (which may occur at the end of each long TTI), if a correspondingLoLat grant 810 is received on the LoLat grant channel 808, that LoLatuser 804 may accordingly decode the LoLat downlink data transmitted onthe TDD carrier.

At the scheduling entity, prior to the LoLat downlink data transmissionon the TDD carrier, it is receiving the regular uplink transmissionsfrom regular users 802. At the time of the LoLat transmission, toaccommodate the downlink transmission of the LoLat data on the TDDcarrier, the scheduling entity may cease receiving any regular uplinkdata transmissions on the TDD carrier, and may begin transmitting thedownlink LoLat data on the TDD carrier. Here, the regular users 802 maycontinue transmitting their regular uplink data on the TDD carrier,since they may not have received any advance warning or indication thatthe scheduling entity would not be listening to their uplinktransmissions on the TDD carrier during the corresponding short TTIs.Following completion of the LoLat downlink transmissions on the TDDcarrier, the scheduling entity may switch back and turn its receiver on,to receive the ongoing further regular uplink data transmissions on theTDD carrier.

In some aspects of the disclosure, the regular users 802 that wereinterrupted by the LoLat downlink transmission might not have anyindication that they were, in fact, interrupted and that their uplinktransmissions were temporarily ignored. That is, the scheduling entityneed not necessarily inform the regular users 802 that their uplinktransmissions are being interrupted/ignored to accommodate the LoLatdownlink transmission.

One potential impact of this scheme may be some degree of inter-cellinterference caused by the scheduling entity, when it transmits itsLoLat downlink transmission on the TDD carrier, upon other neighboringscheduling entities (e.g., where two high-power base stations neighborone another). Furthermore, inter-user interference may occur, whereinthe regular users 802, which may continue to transmit their uplink dataon the TDD carrier, may impact the reception performance of the LoLatuser 804.

Accordingly, in a further aspect of the disclosure, the regular users802 may have the capability to monitor the FDD downlink carrier,including transmissions on the LoLat grant channel 808, during theirtransmissions of regular uplink data on the TDD carrier. Here, in someexamples, the FDD downlink carrier may include further controlinformation directed to the regular users 802, which may indicate tothose users that their uplink transmissions on the TDD carrier are beinginterrupted for a LoLat user. In this way, the regular users 802 may beenabled to cease their uplink transmissions on the TDD carrier, reducingor preventing their potential jamming of the LoLat user's 804 receptionof the LoLat downlink data on the TDD carrier. In a further aspect ofthe disclosure, a guard time 806 may be utilized after the end of theLoLat downlink transmission, before the regular users 802 resume theirtransmissions of regular uplink data on the TDD carrier. The guard time806 may be eliminated in some examples.

FIG. 9 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink and downlink data withdifferent latency targets utilizing a TDD data carrier paired with FDDcomponent carriers for control information. In this illustration, timemoves forward in the downward direction, and communication signalsbetween the illustrated entities are denoted with arrows between thelines below the respective entities. As illustrated, a scheduling entity801 is in communication with a plurality of subordinate entities 104,including a regular user 802 and a LoLat user 804. Each entity 801, 802,and 804 is configured for communication over a TDD carrier, and an FDDcarrier. The respective TDD and FDD carriers are illustratedschematically with the two vertical lines extending down from eachrespective entity.

FIG. 9 is described below in conjunction with a flow chart illustratedin FIG. 10. That is, FIG. 10 is a flow chart illustrating an exemplaryprocess 1000 for resource assignment and re-assignment utilizing a TDDdata carrier paired with FDD component carriers for control informationin accordance with some aspects of the present disclosure. The process1000 is described from the point-of-view of a scheduling entity 801, andmay accordingly, as described in conjunction with FIG. 9, be operationalat the scheduling entity 102 described above in conjunction with FIGS. 1and/or 2. In other examples within the scope of the present disclosure,the process 1000 may be operational by a general purpose processor, aprocessing system 214 as described above and illustrated in FIG. 2, orany suitable means for carrying out the described functions. Thespecific order of steps or blocks shown in FIG. 10 is merely exemplaryin nature, and in various aspects of the disclosure, these steps orblocks may occur in any suitable order, with some examples including twoor more steps or blocks occurring simultaneously.

At block 1002, the scheduling entity 801 may transmit a first assignmentor grant 820 of time-frequency resources to at least one subordinateentity on the FDD downlink component carrier. Any suitable controlchannel on the FDD downlink component carrier may be utilized for thefirst resource assignment, such as a downlink assignment channel. Here,the first resource assignment 820 may be configured to indicate whichtime-frequency resource or resources are assigned to the respectivesubordinate entities for regular transmissions of uplink data, that is,transmissions utilizing the long TTI. In accordance with the firstresource assignment 820, at block 1004, the scheduling entity 801 mayreceive regular uplink data 822 on the TDD uplink carrier from the atleast one subordinate entity (e.g., the subordinate entities 802 and804) utilizing the long TTI. Here, with reference to FIG. 8, thisregular uplink data 822 may correspond to the transmissions from regularusers 802. As illustrated in FIG. 9 with the dashed-line arrow, regularuplink data may optionally be transmitted from the second subordinateentity 804, depending on the contents of the first resource assignment820 and whether the second subordinate entity 804 is configured totransmit uplink data transmissions utilizing the long TTI.

The blocks 1002 and 1004 may repeat, or be iterated a plurality of timesin various examples, as regular uplink data 822 may continue to betransmitted from the subordinate entities. However, at any given time,it may arise that the scheduling entity 801 may wish to transmit LoLatdata to a particular subordinate entity (i.e., the LoLat user 804).Accordingly, at block 1006, the scheduling entity 801 may transmit anassignment or grant 820 of time-frequency resources on the LoLat grantchannel 808 on the FDD downlink component carrier, to at least onesubordinate entity (e.g., the LoLat user 804). Here, the resourceassignment 810 may indicate for the LoLat user 804 to receive LoLatdownlink data from the scheduling entity 801 utilizing at least oneshort TTI. Specifically, the resource assignment 810 may includeinformation identifying a particular subordinate entity 804, andinformation identifying time-frequency resources granted on the TDDcarrier for the LoLat downlink transmission.

At block 1008, the scheduling entity 801 may optionally (as indicated bythe dashed-line box 1008) transmit an uplink scheduling grantmodification 809 on any suitable channel on the FDD downlink componentcarrier. Here, the uplink scheduling grant modification 809 may instructthe regular users such as the first subordinate entity 802, havinggranted time-frequency resources for long-TTI uplink transmissions, topuncture their uplink transmissions during at least one designated shortTTI (i.e., the short TTI(s) corresponding to the LoLat grant 810).

Block 1010 represents operations at one or more subordinate entities,such as regular users 802 and LoLat user(s) 804. That is, in response tothe uplink grant modification 809, the regular users (e.g., the firstsubordinate entity 802) may optionally puncture their previouslyscheduled uplink data transmissions that utilize the long TTI. Thepuncturing is an optional step, operable on subordinate entitiesconfigured to monitor the control channels on the FDD downlink componentcarrier while transmitting uplink data on the TDD carrier.

At block 1012, in accordance with the resource assignment 810, thescheduling entity 801 may transmit the LoLat downlink data 824 on theTDD carrier. In some examples, the transmission of the LoLat grant 810and the LoLat downlink data 824 may occur at the same time, i.e., duringthe same short TTI. However, this is not necessarily the case, and inother examples, the LoLat downlink grant 810 and the LoLat downlink datamay be transmitted during completely non-overlapping short TTIs, or, asillustrated in FIG. 8, a single short TTI may be utilized for the LoLatdownlink grant 810, which may overlap with any number (including zero)of short TTIs during which the LoLat downlink data is transmitted on theTDD carrier.

Blocks 1014 and 1016 represent operations at one or more subordinateentities, such as the regular users 802 and, in some examples, LoLatuser(s) 804. That is, at block 1014, the regular subordinate entitiesmay optionally wait for a suitable gap or guard time 806, after the endof the scheduled LoLat downlink transmissions 824. This guard time 806may for example compensate for any propagation delay or other airinterface delay, allowing full completion of the LoLat downlinktransmissions to all users in the service area prior to resumption ofany uplink transmissions on the TDD carrier. At block 1016, the regularsubordinate entities (i.e., regular user 802) may resume their regularuplink data transmissions on the TDD carrier when transmission of theLoLat downlink data has been completed (and optionally after the guardtime 806). Accordingly, at block 1018, the scheduling entity 802 mayresume receiving regular uplink data on the TDD carrier from one or moresubordinate entities utilizing the long TTI.

By utilizing the above scheme, pairing a TDD carrier for datatransmissions with an FDD carrier for control channel transmissions, athin LoLat grant channel 808 can enable a scheduling entity to rapidlyand dynamically control the multiplexing of uplink and downlink data onthe TDD carrier having at least two different data types or categories,from a set of subordinate entities.

FDD-TDD Carrier Pairing: Multiplexing LoLat UL on Regular DL

FIG. 11 illustrates yet another example of pairing a TDD carrier with anFDD carrier, providing for multiplexing of LoLat uplink transmissions(i.e., transmissions from a subordinate entity) with regular downlinktransmissions (i.e., transmissions from a scheduling entity). In theillustrated example, the TDD carrier is illustrated in much the same wayas the TDD carrier in FIG. 8, with downlink resources shown with ascheduling entity transmitting “regular” downlink data utilizing a longTTI to plurality of users (subordinate entities). Here, as will bedescribed in further detail below, at the request of a subordinateentity, the scheduling entity may modify the scheduling assignment orgrant of time-frequency resources, interrupting the ongoing downlinktransmissions on the TDD carrier, to enable uplink transmissions (e.g.,LoLat data transmissions) on the TDD carrier.

In the illustrated example, a control channel for controlling the datacarried on the TDD carrier is carried on an FDD downlink componentcarrier. That is, the FDD band includes in its downlink componentcarrier a LoLat grant channel 1108 in which a subordinate entity mayreceive information such as a LoLat uplink grant 1110, which may carrygrant information for the LoLat user 1104 that requested LoLatscheduling to utilize for transmitting a LoLat uplink transmission. TheFDD band further includes in its downlink component carrier a thincontrol channel 1112 that may carry a downlink grant modification 1114,which modifies a downlink time-frequency resource grant corresponding tothe regular users' 1102 downlink data reception on the TDD carrier.

In the illustration, the LoLat grant 1110 is shown as occupying a widerbandwidth than the DL grant modification 1114. This represents that,while the DL grant modification 1114 may simply be a few bitsrepresenting the frequency resources that are being re-allocated awayfrom a regular user 1102, and a number of short TTIs, the LoLat grant1110 may include more precise information relating to the LoLat resourceassignment such as a user ID, the assignment information, a modulationand coding scheme, etc.

Furthermore, a control channel for enabling subordinate entities toquickly send information to the scheduling entity is carried on an FDDuplink component carrier. That is, the FDD band includes in its uplinkcomponent carrier a thin feedback channel 1116 in which the schedulingentity may receive feedback information from subordinate entities suchas a LoLat scheduling request 1118.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for downlink transmissionson the TDD carrier to one or more subordinate entities (e.g., Users A-F)by utilizing any suitable downlink grant channel (not necessarily one ofthe illustrated channels). As these downlink transmissions are ongoing,if a particular subordinate entity, denoted as the LoLat user 1104,wishes to request resources for a LoLat uplink transmission, thissubordinate entity may transmit a LoLat scheduling request 1118 on thethin feedback channel 1116 on the FDD uplink component carrier. Here,the LoLat scheduling request 1118 may utilize the short TTI, althoughthis is not necessarily always the case. In response, if the schedulingentity wishes to grant the requested LoLat resource, the schedulingentity 102 may transmit, on the FDD downlink component carrier, a LoLatgrant 1110 that informs the LoLat user 1104 that transmitted the LoLatuser scheduling request 1118 of its granted resources. After a suitabledelay to enable the LoLat user to receive and process the LoLat grant1110 and prepare for its LoLat uplink transmission, the schedulingentity may further transmit, on the thin control channel 1112, adownlink grant modification that informs the regular users 1102 that arereceiving downlink data transmissions on the TDD carrier, that some orall of their granted resources are being modified or removed to make wayfor the LoLat transmission.

Because the data carrier is a TDD carrier, during transmission of theuplink data by the LoLat user 1104, the downlink data transmissions tothe regular users 1102 utilizing the long TTI are punctured, ceased, orsuspended. During this time, the LoLat user 1104 may transmit its LoLatuplink transmission on the TDD carrier, resulting in an orthogonalmultiple access scheme between regular downlink transmissions and LoLatuplink transmissions on the TDD carrier.

In some examples, just prior to the time at which LoLat uplinktransmissions are scheduled to commence, the scheduling entity maysuspend its regular downlink data transmissions on the TDD carrier. Thatis, a gap or guard time 1106 may optionally be utilized whenmultiplexing LoLat uplink transmissions and regular downlinktransmissions on the TDD carrier. Here, this guard time 1106 may forexample compensate for any propagation delay or other air interfacedelay, allowing full completion of the regular downlink transmissions toall users in the service area prior to the time when the LoLat uplinktransmissions commence on the TDD carrier.

In the illustration, the downlink grant modification is illustrated asappearing at the same time as the downlink resources are modified. Theneed for advance timing of the grant modification can be avoided becausethe downlink grant modification and the downlink data may be bufferedand post-processed by the receiving regular UEs, as described above.

FIG. 12 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink and downlink data withdifferent latency targets utilizing a TDD data carrier paired with FDDcomponent carriers for control information. In this illustration, timemoves forward in the downward direction, and communication signalsbetween the illustrated entities are denoted with arrows between thelines below the respective entities. As illustrated, a scheduling entity1101 is in communication with a plurality of subordinate entities 104,including a regular user 1102 and a LoLat user 1104. Each entity 1101,1102, and 1104 is configured for communication over a TDD carrier, andan FDD carrier. The respective TDD and FDD carriers are illustratedschematically with the two vertical lines extending down from eachrespective entity.

FIG. 12 is described below in conjunction with a flow chart illustratedin FIG. 13. That is, FIG. 13 is a flow chart illustrating an exemplaryprocess 1300 for resource assignment and re-assignment utilizing a TDDdata carrier paired with FDD component carriers for control informationin accordance with some aspects of the present disclosure. The process1300 is described from the point-of-view of a scheduling entity 1101,and may accordingly, as described in conjunction with FIG. 12, beoperational at the scheduling entity 102 described above in conjunctionwith FIGS. 1 and/or 2. In other examples within the scope of the presentdisclosure, the process 1300 may be operational by a general purposeprocessor, a processing system 214 as described above and illustrated inFIG. 2, or any suitable means for carrying out the described functions.The specific order of steps or blocks shown in FIG. 13 is merelyexemplary in nature, and in various aspects of the disclosure, thesesteps or blocks may occur in any suitable order, with some examplesincluding two or more steps or blocks occurring simultaneously.

At block 1302, the scheduling entity 1101 may transmit a firstassignment or grant 1120 of time-frequency resources to at least onesubordinate entity on the FDD downlink component carrier. Any suitablecontrol channel on the FDD downlink component carrier may be utilizedfor the first resource assignment, such as a downlink assignmentchannel. Here, the first resource assignment 1120 may be configured toindicate which time-frequency resource or resources are assigned to therespective subordinate entities for receiving regular transmissions ofdownlink data, that is, transmissions utilizing the long TTI. Inaccordance with the first resource assignment 1120, at block 1304, thescheduling entity 1101 may transmit regular downlink data 1122 on theTDD downlink carrier to the at least one subordinate entity (e.g., thesubordinate entities 1102 and 1104) utilizing the long TTI. Here, withreference to FIG. 11, this regular uplink data 1122 may correspond tothe downlink transmissions to regular users 1102. As illustrated in FIG.12 with the dashed-line arrow, regular downlink data may optionally betransmitted to the second subordinate entity 1104, depending on thecontents of the first resource assignment 1120 and whether the secondsubordinate entity 1104 is configured to receive downlink datatransmissions utilizing the long TTI.

The blocks 1302 and 1304 may repeat, or be iterated a plurality of timesin various examples, as regular downlink data 1122 may continue to betransmitted to the subordinate entities. However, at any given time, itmay arise that the subordinate entity 1104 (i.e., the LoLat user 1104)may wish to transmit LoLat uplink data to the scheduling entity 1101.Accordingly, at block 1306, the scheduling entity 1101 may receive aLoLat scheduling request 1118 on the thin feedback channel 1116 on theFDD uplink component carrier from the LoLat user 1104 (i.e., the secondsubordinate entity 1104). The LoLat scheduling request 1118 may includeinformation identifying the requesting subordinate entity 1104, andincluding any pertinent information relating to the LoLat data desiredto be transmitted.

At block 1308, the scheduling entity 1101 may transmit a secondassignment or grant 1110 of time-frequency resources on a LoLat grantchannel 1108 on the FDD downlink component carrier, to the requestingsubordinate entity 1104. Here, the second resource assignment 1110 mayinclude information identifying the requesting subordinate entity 1104,and information identifying time-frequency resources granted on the TDDuplink carrier for the LoLat uplink transmission.

At optional block 1310, the scheduling entity 1101 may suspend itsregular downlink data transmissions 1122 on the TDD carrier just priorto the time at which LoLat uplink transmissions are scheduled tocommence. That is, a gap or guard time 1106 may optionally be utilizedwhen multiplexing LoLat uplink transmissions 1124 and regular downlinktransmissions 1122 on the TDD carrier.

At block 1312, the scheduling entity 1101 may transmit a downlinkscheduling grant modification 1114 on the thin control channel 1112 onthe FDD downlink component carrier. Here, the downlink scheduling grantmodification 1114 may instruct the regular users such as the firstsubordinate entity 1102, having granted time-frequency resources forlong-TTI downlink transmissions, to ignore any uplink transmissionsduring at least one designated short TTI. That is, since thetransmissions during that TTI will be LoLat uplink transmissions fromthe LoLat user 1104, not directed to the regular user 1102, the data maynot be decodable by the regular user 1102 and can be ignored by theregular user 1102 during post-processing of the corresponding long TTI.

Block 1314 represents operations at one or more subordinate entities,such as the LoLat user 1104. That is, in response to the second resourceassignment 1110, the LoLat user (i.e., the second subordinate entity1104) may transmit the LoLat uplink data 1124 utilizing the assignedtime-frequency resources on the TDD carrier.

In some examples, the transmission of the downlink scheduling grantmodification 1114 at block 1312, and the transmission of the LoLatuplink data 1124 on the TDD carrier at block 1314 (and the correspondingsuspension of downlink data transmissions on the TDD carrier, notincluding any guard time that may be added), may occur simultaneously.That is, these transmissions may be multiplexed, for example, utilizingdifferent time-frequency resources. In other examples, thesetransmissions may be at different times, according to the details of aparticular implementation. That is, the regular users 1102 may beconfigured to buffer or cache the contents of the thin control channel1112 and the TDD carrier, such that the ignoring of data during thedesignated short TTI(s) may be performed during post-processing by theregular users 1102.

At block 1316, the scheduling entity 1101 may receive the LoLat uplinkdata 1124 transmitted from the requesting subordinate entity 1104utilizing the short TTI on the TDD carrier. At block 1318, thescheduling entity 1101 may resume transmitting the regular downlink data1122 on the TDD carrier, to one or more subordinate entities, such asthe regular user 1102 utilizing the long TTI.

By utilizing the above scheme, pairing a TDD carrier for uplink datatransmissions with FDD carriers for control channel transmissions, athin control channel 1112 can enable a scheduling entity to multiplexuplink and downlink data having at least two different data types orcategories, for set of subordinate entities.

TDD-TDD Carrier Pairing

In a further aspect of the disclosure, rather than pairing an FDDcarrier with a TDD carrier, two TDD carriers may be paired with oneanother in a way that can enable full duplex communication. FIG. 14illustrates one example of a pairing of two TDD component carriers (CC).In this illustration, a first CC (component carrier 1 or CC1) is pairedwith a second CC (component carrier 2 or CC2). The horizontal axisrepresents time, and the vertical axis represents frequency (not toscale). Both CC1 and CC2 are TDD carriers, wherein uplink time slots,indicated with a U, are time-multiplexed with downlink time slots,indicated with a D on each respective carrier. Additionally, some timeslots are identified as special time slots, and indicated with an S,described further below. Herein, a time slot may correspond to anysuitable duration of time, and may correspond to other nomenclature suchas a transmission time interval (TTI), subframe, frame, symbol duration,etc.

If only CC1 were usable by a communication device, it is seen that onlydownlink, uplink, or special time slots exist at any single time. Theillustration shows two different types of frames, identified asConfiguration A and Configuration B. In the first frame, identified asConfiguration A, there is the same number of uplink time slots U anddownlink time slots D, with two of the time slots identified as specialtime slots S. In the second frame, identified as Configuration B, mostof the time slots are downlink time slots D, with one uplink time slot Uand one special time slot S. The third frame is shown as anotherConfiguration A frame. These configurations are merely one example,which corresponds to some existing configurations defined in TD-LTEstandards.

At any moment, for example, during the second frame identified asConfiguration B, if the communication device has a need to send feedbackon the uplink, it may not be presented with such an opportunity, becauseit is faced with a long stretch of downlink-only time slots. Here, thefeedback would need to be buffered at least until the next opportunityis presented in the third time slot of the third frame.

Therefore, in an aspect of the present disclosure, the first TDDcomponent carrier CC1 may be paired with a second TDD component carrierCC2. Here, CC2 may implement an inverse, conjugate, or complementarytransmit/receive organization relative to that of CC1. In the presentdisclosure, the terms inverse, complementary, and conjugate are utilizedinterchangeably, generally referring to a configuration wherein at leastsome of the downlink time slots D in CC1 are paired with uplink timeslots U in CC2, and at least some of the uplink time slots U in CC1 arepaired with downlink time slots D in CC2. The configuration illustratedis merely exemplary in nature, and other configurations may be utilizedwithin the scope of the present disclosure, some of which may pair alltime slots across the two component carriers, and others of which mayinclude some unpaired uplink/downlink time slots.

As shown, the Configuration A frame is paired with a Configuration −Aframe, wherein Configuration −A represents the inverse (or conjugate) ofConfiguration A. Likewise, the Configuration B frame is paired with aConfiguration −B frame.

The special time slot, indicated with the S, in the illustrated examplemay be utilized for downlink-to-uplink switching. That is, withreference to communication by a subordinate entity 104, when utilizing aTDD carrier, where the timing for both the uplink and downlinktransmissions is driven by a scheduling entity 102, there may be a needfor a certain time gap when transitioning from a downlink time slot Dand an uplink time slot U. That is, there is a certain propagation delaybetween the transmission of the downlink time slot D from the schedulingentity 102 to the subordinate entity 104, as well as between thetransmission of the uplink time slot U from the subordinate entity 104to the scheduling entity 102. To account for these propagation delays,special time slots S insert a gap between the end of a downlink timeslot D and the beginning of an uplink time slot U, so that thescheduling entity 102 and the subordinate entity 104 can maintainsynchronization. Here, the gap may correspond to a time when neitheruplink nor downlink communications occur. The length of the gap in thespecial time slot S can be configured in accordance with the size of thecell.

In various aspects of the disclosure, the special time slots S in onecomponent carrier can be paired with any suitable time slot on itspaired component carrier, including a downlink time slot D, an uplinktime slot U, or another special time slot S. In some examples, such asthe illustrated example in FIG. 14, each of the special time slots S inone component carrier (CC1) may be mapped (e.g., time-aligned) to arespective downlink time slot in its paired component carrier (CC2).However, this is merely one example, and is not intended to be limitingin nature.

In a further example, special time slots S may be inserted in theinverse or paired component carrier CC2 as needed, in betweentransitions from downlink time slots to uplink time slots.

In some examples, the paired component carriers may be inter-bandcarriers. That is, each of the component carriers CC1 and CC2 may lie ina different band from that of its paired component carrier. By placingthe component carriers in different bands, the RF functionality at adevice such as a scheduling entity 102 and a subordinate entity 104 canbe improved, reducing interference and de-sense between the respectivecarriers. This is not a requirement, however, and intra-band componentcarriers may be utilized within the scope of the present disclosure;however, it may be beneficial in such case to choose component carriersthat are as far apart in frequency as feasible.

The illustration in FIG. 14 shows, as one example, two paired TDDcomponent carriers having essentially the same bandwidth. That is, eachcomponent carrier has the same width in the vertical frequencydimension. Here, if two TDD component carriers of the same bandwidth arepaired with one another, one of the benefits of a conventional TDDcarrier may be lost. That is, conventional TDD has an advantage that,depending on the characteristics of the traffic, it can be decided howmany time slots can be used for downlink traffic, and how many timeslots can be used for uplink traffic, enabling a dynamic assignment andproviding for the most efficient use of available resources. Thisflexibility would be lost if all time slots in one direction in onecomponent carrier are paired with time slots in the other direction inits paired component carrier, if the paired component carriers have thesame bandwidth. That is, with such a configuration the sum of downlinktime slots on both component carriers would be equal to the sum ofuplink time slots on both component carriers.

FIG. 15 illustrates a conjugate pairing of component carriers inaccordance with a further aspect of the present disclosure, configuredto afford a degree of flexibility in the allocation of uplink anddownlink time slots.

The reason full duplex is desired is not necessarily for the benefit ofthe traffic channels. Rather, as described above, full duplexcommunication may be desirable because it can provide additionalcontrol, e.g., by the enablement of thin feedback and a thin grant fordynamic modification of the communication.

Accordingly, as illustrated in FIG. 14, a first TDD component carrier,CC1, having a wide bandwidth (e.g., 100 MHz) may be paired with a secondTDD component carrier, CC2, having a narrow bandwidth (e.g., 10 MHz).The ratio between the bandwidth of the two component carriers need notbe the 10:1 ratio given here, but any suitable ratio may be utilizedwithin the scope of the present disclosure. The choice of the ratio maybe made in accordance with characteristics of the traffic being carriedon the uplink and downlink, such as the degree of asymmetry betweenuplink and downlink traffic. For example, traffic that is substantiallyheavier on the downlink side could be accommodated by deploying a largernumber of downlink time slots on the wider bandwidth component carrier.

In some examples, the bandwidth of one or both of the TDD componentcarriers may be selected according to the bandwidth desired or needed;and in some examples, the bandwidth of one or both of the TDD componentcarriers may be configurable by the scheduling entity or the subordinateentity.

TDD-TDD Carrier Pairing: Multiplexing LoLat UL on Regular UL

FIG. 16 illustrates one example of pairing a first TDD component carrierwith a second TDD component carrier, providing for multiplexing of LoLatuplink transmissions with regular uplink transmissions (i.e.,transmissions from a subordinate entity) on the primary TDD componentcarrier. In the illustrated example, the primary TDD component carrieris illustrated in much the same way as the TDD carrier in FIG. 5, withuplink resources allocated to different users being represented by thelarge blocks spanning a long TTI. Here, as will be described in furtherdetail below, a subordinate entity (e.g., a UE) may request, and begranted, resources for a LoLat transmission that may be multiplexed withthe regular uplink transmissions from other users. At the bottom of thefigure, resources on a second TDD component carrier are allocated foruse.

In the illustrated example, control channels for controlling the uplinkdata transmissions on the primary TDD component carrier are carried onthe secondary TDD component carrier. That is, the secondary TDDcomponent carrier includes a thin control channel 1606, which may carryuplink grant modification information 1608 that modifies an uplinkresource grant corresponding to the subordinate entity (i.e., theregular user 1602) uplink transmission on the primary TDD componentcarrier. Further, the secondary TDD component carrier includes a LoLatgrant channel 1610, which may carry grant information 1612 for thesubordinate entity that requests LoLat scheduling (i.e., the LoLat user1604) to utilize in a LoLat uplink transmission on the primary TDDcomponent carrier.

Further, in addition to data carriers, the primary TDD component carrierincludes a thin feedback channel 1614 that a subordinate entity (i.e.,the LoLat user 1604) can utilize to transmit information such as a LoLatscheduling request 1616.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for uplink transmissions onthe primary TDD component carrier to one or more subordinate entities(e.g., Users A-F) by utilizing any suitable downlink grant channel (notnecessarily one of the illustrated channels). As these uplinktransmissions are ongoing, if a particular subordinate entity, denotedas the LoLat user 1604, wishes to request resources for a LoLat uplinktransmission, this subordinate entity may transmit a LoLat schedulingrequest 1616 on the thin feedback channel 1614 on the primary TDDcomponent carrier. Here, the LoLat scheduling request 1616 may utilizethe short TTI, although this is not necessarily always the case. Inresponse, if the scheduling entity wishes to grant the requested LoLatresource, the scheduling entity 102 may transmit, on the secondary TDDcomponent carrier, an uplink grant modification 1608 on the thin controlchannel 1606, and a LoLat grant 1612 on the LoLat grant channel 1610.Here, the an uplink grant modification 1608 on the thin control channel1606 may be configured to inform all of the subordinate entities thatare utilizing granted uplink time-frequency resources on the primary TDDcomponent carrier that some or all of their granted resources are beingmodified or removed, to make way for the LoLat transmission. Further,the LoLat grant 1612 on the LoLat grant channel 1610 may be configuredto inform the subordinate entity that transmitted the LoLat schedulingrequest (i.e., the LoLat user 1604) of its granted time-frequencyresources. In the illustration, the LoLat grant 1612 is shown asoccupying a wider bandwidth than the UL grant modification 1608. Thisrepresents that, while the UL grant modification 1608 may simply be afew bits representing the frequency resources that are beingre-allocated away from a regular user 1602, and a number of short TTIs,the LoLat grant 1612 may include more precise information relating tothe LoLat resource assignment such as a user ID, the assignmentinformation, a modulation and coding scheme, etc. Accordingly, the LoLatuser 1604 may transmit its LoLat uplink transmission on the primary TDDcomponent carrier, while other regular users 1602 (such as Users D, E,and F) may cease their uplink transmissions, resulting in an orthogonalmultiple access scheme between regular and LoLat uplink transmissions onthe TDD carrier.

In this example, the regular users 1602 (e.g., subordinate entities104), whose uplink resources were punctured, may benefit from having anability to quickly decode the uplink grant modification 1608. That is,the time from when the uplink grant modification 1608 is received at theregular user 1602, until that user ceases its uplink transmissions, maybe very short. To accommodate the quick reaction time, the subordinateentity 104 may be configured for a fast suspension of its uplinktransmissions, e.g., by driving a zero input to a power amplifier withinthe transceiver 310, or in another example, being capable of quicklyturning off the power amplifier. Furthermore, the LoLat user 1604 alsomay have only a brief time from the receiving of its LoLat uplink grant1612, and its transmission of LoLat uplink data. Accordingly, fastprocessing of the LoLat grant 1612 and transmission utilizing thescheduled time-frequency resources would be beneficial and reducelatency.

FIG. 17 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink data with different latencytargets utilizing a primary TDD component carrier paired with asecondary TDD component carrier. In this illustration, time movesforward in the downward direction, and communication signals between theillustrated entities are denoted with arrows between the lines below therespective entities. As illustrated, a scheduling entity 1601 is incommunication with a plurality of subordinate entities 104, including aregular user 1602 and a LoLat user 1604. Each entity 1601, 1602, and1604 is configured for communication over a primary TDD componentcarrier, and a secondary TDD component carrier. The respective primaryand secondary TDD component carriers are illustrated schematically withthe two vertical lines extending down from each respective entity.

FIG. 17 is described below in conjunction with a flow chart illustratedin FIG. 18. That is, FIG. 18 is a flow chart illustrating an exemplaryprocess 1800 for resource assignment and re-assignment in accordancewith some aspects of the present disclosure. The process 1800 isdescribed from the point-of-view of a scheduling entity 1601, and mayaccordingly, as described in conjunction with FIG. 17, be operational atthe scheduling entity 102 described above in conjunction with FIGS. 1and/or 2. In other examples within the scope of the present disclosure,the process 1800 may be operational by a general purpose processor, aprocessing system 214 as described above and illustrated in FIG. 2, orany suitable means for carrying out the described functions. Thespecific order of steps or blocks shown in FIG. 18 is merely exemplaryin nature, and in various aspects of the disclosure, these steps orblocks may occur in any suitable order, with some examples including twoor more steps or blocks occurring simultaneously.

At block 1802, the scheduling entity 1601 may transmit a firstassignment or grant 1620 of time-frequency resources to at least onesubordinate entity on the secondary TDD component carrier. Any suitablecontrol channel may be utilized for the first resource assignment, suchas a downlink assignment channel. Here, the first resource assignment1620 may be configured to indicate which time-frequency resource orresources are assigned to the respective subordinate entities forregular transmissions of uplink data, that is, transmissions utilizingthe long TTI. In accordance with the first resource assignment 1620, atblock 1804, the scheduling entity 1601 may receive regular uplink data1622 on the primary TDD component carrier from the at least onesubordinate entity (e.g., the subordinate entities 1602 and 1604)utilizing the long TTI. Here, with reference to FIG. 16, this regularuplink data 1622 may correspond to the transmissions from regular users1602. As illustrated in FIG. 17 with the dashed-line arrow, regularuplink data may optionally be transmitted from the second subordinateentity 1604, depending on the contents of the first resource assignment1620 and whether the second subordinate entity 1604 is configured totransmit uplink data transmissions utilizing the long TTI.

The blocks 1802 and 1804 may repeat, or be iterated a plurality of timesin various examples, as regular uplink data 1622 may continue to betransmitted from the subordinate entities. However, at any given time,it may arise that the subordinate entity 1604 (i.e., the LoLat user1604) may wish to transmit LoLat data to the scheduling entity 1601.Accordingly, at block 1806, the scheduling entity 1601 may receive aLoLat scheduling request 1616 on the thin feedback channel 1614 on theprimary TDD component carrier from the LoLat user 1604 (i.e., the secondsubordinate entity 1604). The LoLat scheduling request 1616 may includeinformation identifying the requesting subordinate entity 1604, andincluding any pertinent information relating to the LoLat data desiredto be transmitted.

At block 1808, the scheduling entity 1601 may transmit an uplinkscheduling grant modification 1608 on the thin control channel 1606 onthe secondary TDD component carrier. Here, the uplink scheduling grantmodification 1608 may instruct the regular users such as the firstsubordinate entity 1602, having granted time-frequency resources forlong-TTI uplink transmissions, to puncture their uplink transmissionsduring at least one designated short TTI. Further at block 1810, thescheduling entity 1601 may transmit a second resource assignment orgrant 1612 of time-frequency resources to the requesting subordinateentity (i.e., the LoLat user 1604) on the LoLat grant channel 1610 onthe secondary TDD component carrier. Here, the second resourceassignment 1612 may include information identifying the requestingsubordinate entity 1604, and information identifying time-frequencyresources granted on the primary TDD component carrier for the LoLatuplink transmission. In some examples, the transmission of the uplinkscheduling grant modification 1608 at block 1808, and the transmissionof the second resource assignment 1612 at block 1810, may occursimultaneously. That is, these transmissions may be multiplexed, forexample, utilizing different time-frequency resources. In otherexamples, these transmissions may be at different times, according tothe details of a particular implementation.

Block 1812 represents operations at one or more subordinate entities,such as regular users 1602 and LoLat user(s) 1604. That is, in responseto the uplink grant modification 1608, the regular users (i.e., thefirst subordinate entity 1602) may puncture their previously scheduleduplink data transmissions that utilize the long TTI. Further, inresponse to the second resource assignment 1612, the LoLat user(s)(i.e., the second subordinate entity 1604) may transmit the LoLat uplinkdata 1624 utilizing the assigned time-frequency resources on the primaryTDD component carrier.

At block 1814, the scheduling entity 1601 may receive the LoLat uplinkdata 1624 transmitted from the requesting subordinate entity 1604utilizing the short TTI on the primary TDD component carrier.

Block 1816 represents operations at one or more subordinate entities,such as the regular users 1602 and, in some examples, LoLat user(s)1604. That is, the regular subordinate entities may resume their regularuplink data transmissions on the primary TDD component carrier whentransmission of the LoLat uplink data 1624 has been completed.Accordingly, at block 1818, the scheduling entity 1602 may resumereceiving regular uplink data 1622 on the primary TDD component carrierfrom one or more subordinate entities utilizing the long TTI.

By utilizing the above scheme, pairing a primary TDD carrier for uplinkdata transmissions and uplink feedback transmissions, with a secondaryTDD component carrier for control channel transmissions, a thin controlchannel 1606 can enable a scheduling entity to multiplex at least twodifferent data types or categories, having different TTIs, for uplinktransmissions from a set of subordinate entities.

TDD-TDD Carrier Pairing: Multiplexing LoLat DL on Regular UL

FIG. 19 illustrates another example of TDD-TDD component carrierpairing, providing for multiplexing of LoLat downlink transmissions(i.e., transmissions from a scheduling entity) with regular uplinktransmissions (i.e., transmissions from a subordinate entity) on theprimary TDD component carrier. In the illustrated example, the primaryTDD component carrier is illustrated in much the same way as the TDDcarrier in FIG. 4, with uplink resources shown with a plurality of users(subordinate entities) transmitting “regular” uplink data utilizing along TTI. Here, as will be described in further detail below, thescheduling entity may modify the scheduling assignment or grant oftime-frequency resources, interrupting the ongoing uplink transmissionson the primary TDD component carrier, with downlink transmissions on theprimary TDD component carrier.

In the illustrated example, a control channel for controlling the userdata carried on the primary TDD component carrier is carried on asecondary TDD component carrier. That is, the secondary TDD componentcarrier includes a LoLat grant channel 1910, in which a subordinateentity may receive information such as a LoLat downlink grant 1912.

In this example, because a secondary TDD component carrier is pairedwith the primary TDD component carrier (e.g., utilizing the conjugatepairing described above), the subordinate entity may always (or most ofthe time) be receiving a control channel in the downlink direction onthe secondary TDD component carrier, even while uplink transmissions areongoing on the primary TDD component carrier. Furthermore, in an aspectof the disclosure, if a particular subordinate entity is not currentlytransmitting uplink data on the primary TDD component carrier, then thatparticular user may be configured always to listen for downlink data onthe primary TDD component carrier.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for uplink transmissions onthe primary TDD component carrier to one or more subordinate entities(e.g., Users A-F) by utilizing any suitable downlink grant channel (notnecessarily one of the illustrated channels).

At any given time, during the regular users' 1902 transmission of theuplink data on the primary TDD component carrier, the scheduling entitymay determine to transmit LoLat downlink data on the primary TDDcomponent carrier. That is, at any time, one or more subordinateentities in communication with the scheduling entity, such as a LoLatuser 1904, may come to need LoLat communication with the network,wherein more stringent latency requirements for communication are neededthan the relatively long latency resulting from the communication byregular users utilizing the long TTI. Thus, in an aspect of the presentdisclosure, the availability of the LoLat grant channel 1910 on thesecondary TDD component carrier may enable dynamic multiplexing of thetraffic for one or more subordinate entities that desire low latencycommunication (hereinafter referred to as LoLat users 1904), who canutilize a short TTI for data traffic, and the traffic for the regularusers 1902, who utilize the long TTI for data traffic.

Accordingly, on the LoLat grant channel 1910 on the secondary TDDcomponent carrier, at any given time, the scheduling entity maybroadcast a LoLat downlink grant 1912. The LoLat downlink grant 1912 maybe structured in any suitable manner. As one example, the LoLat downlinkgrant 1912 may include information to identify one or more LoLat usersfor which LoLat downlink data is being granted, information identifyingtime-frequency resources being allocated to the user, and any othersuitable information regarding receiving and decoding of the downlinkdata.

At the same time, on the primary TDD component carrier, the schedulingentity may broadcast LoLat downlink data to the LoLat user(s) 1904, inaccordance with the LoLat downlink grant 1912. That is, in someexamples, the LoLat downlink grant 1912 and the LoLat downlink data maybe transmitted at the same time, i.e., during the same short TTI.However, this is not necessarily the case, and in other examples, theLoLat downlink grant 1912 and the LoLat downlink data may be transmittedduring completely non-overlapping short TTIs, or, as illustrated in FIG.19, a single short TTI may be utilized for the LoLat downlink grant1912, which may overlap with any number (including zero) of short TTIsduring which the LoLat downlink data is transmitted on the primary TDDcomponent carrier.

That is, the LoLat user 1904 (i.e., the subordinate entity addressed inthe LoLat grant 1912) may be configured to receive and buffer the frameon the primary TDD component carrier, even if it is not activelyreceiving the regular downlink data on the primary TDD componentcarrier. Upon processing the LoLat downlink grant (which may occur atthe end of each long TTI), if a corresponding LoLat grant 1912 isreceived on the LoLat grant channel 1910, that LoLat user 1904 mayaccordingly decode the LoLat downlink data transmitted on the primaryTDD component carrier.

At the scheduling entity, prior to the LoLat downlink data transmissionon the primary TDD component carrier, it is receiving the regular uplinktransmissions from regular users 1902. At the time of the LoLattransmission, to accommodate the downlink transmission of the LoLat dataon the primary TDD component carrier, the scheduling entity may ceasereceiving any regular uplink data transmissions on the primary TDDcomponent carrier, and may begin transmitting the downlink LoLat data onthe primary TDD component carrier. Here, the regular users 1902 maycontinue transmitting their regular uplink data on the primary TDDcomponent carrier, since they may not have received any advance warningor indication that the scheduling entity would not be listening to theiruplink transmissions on the primary TDD component carrier during thecorresponding short TTIs. Following completion of the LoLat downlinktransmissions on the primary TDD component carrier, the schedulingentity may switch back and turn its receiver on, to receive the ongoingfurther regular uplink data transmissions on the primary TDD componentcarrier.

In some aspects of the disclosure, the regular users 1902 that wereinterrupted by the LoLat downlink transmission might not have anyindication that they were, in fact, interrupted and that their uplinktransmissions were temporarily ignored. That is, the scheduling entityneed not necessarily inform the regular users 1902 that their uplinktransmissions are being interrupted/ignored to accommodate the LoLatdownlink transmission.

One potential impact of this scheme may be some degree of inter-cellinterference caused by the scheduling entity, when it transmits itsLoLat downlink transmission on the primary TDD component carrier, uponother neighboring scheduling entities (e.g., where two high-power basestations neighbor one another). Furthermore, inter-user interference mayoccur, wherein the regular users 1902, which may continue to transmittheir uplink data on the primary TDD component carrier, may impact thereception performance of the LoLat user 1904.

Accordingly, in a further aspect of the disclosure, the regular users1902 may have the capability to monitor the secondary TDD componentcarrier, including transmissions on the LoLat grant channel 1910, duringtheir transmissions of regular uplink data on the primary TDD componentcarrier. Here, in some examples, the secondary TDD component carrier mayinclude further control information directed to the regular users 1902,which may indicate to those users that their uplink transmissions on theprimary TDD component carrier are being interrupted for a LoLat user. Inthis way, the regular users 1902 may be enabled to cease their uplinktransmissions on the primary TDD component carrier, reducing orpreventing their potential jamming of the LoLat user's 1904 reception ofthe LoLat downlink data on the primary TDD component carrier. In afurther aspect of the disclosure, a guard time 1906 may be utilizedafter the end of the LoLat downlink transmission, before the regularusers 1902 resume their transmissions of regular uplink data on theprimary TDD component carrier. The guard time 1906 may be eliminated insome examples.

FIG. 20 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink and downlink data withdifferent latency targets utilizing a paired set of primary andsecondary TDD carriers. In this illustration, time moves forward in thedownward direction, and communication signals between the illustratedentities are denoted with arrows between the lines below the respectiveentities. As illustrated, a scheduling entity 1901 is in communicationwith a plurality of subordinate entities 104, including a regular user1902 and a LoLat user 1904. Each entity 1901, 1902, and 1904 isconfigured for communication over primary and secondary TDD componentcarriers. The respective primary and secondary TDD component carriersare illustrated schematically with the two vertical lines extending downfrom each respective entity.

FIG. 20 is described below in conjunction with a flow chart illustratedin FIG. 21. That is, FIG. 21 is a flow chart illustrating an exemplaryprocess 2100 for resource assignment and re-assignment utilizing apaired set of primary and secondary TDD carriers in accordance with someaspects of the present disclosure. The process 2100 is described fromthe point-of-view of a scheduling entity 1901, and may accordingly, asdescribed in conjunction with FIG. 20, be operational at the schedulingentity 102 described above in conjunction with FIGS. 1 and/or 2. Inother examples within the scope of the present disclosure, the process2100 may be operational by a general purpose processor, a processingsystem 214 as described above and illustrated in FIG. 2, or any suitablemeans for carrying out the described functions. The specific order ofsteps or blocks shown in FIG. 21 is merely exemplary in nature, and invarious aspects of the disclosure, these steps or blocks may occur inany suitable order, with some examples including two or more steps orblocks occurring simultaneously.

At block 2102, the scheduling entity 1901 may transmit a firstassignment or grant 1920 of time-frequency resources to at least onesubordinate entity on the secondary TDD component carrier. Any suitablecontrol channel on the secondary TDD component carrier may be utilizedfor the first resource assignment 1920, such as a downlink assignmentchannel. Here, the first resource assignment 1920 may be configured toindicate which time-frequency resource or resources are assigned to therespective subordinate entities for regular transmissions of uplinkdata, that is, transmissions utilizing the long TTI. In accordance withthe first resource assignment 1920, at block 2104, the scheduling entity1901 may receive regular uplink data 1922 on the primary TDD componentcarrier from the at least one subordinate entity (e.g., the subordinateentities 1902 and 1904) utilizing the long TTI. Here, with reference toFIG. 19, this regular uplink data 1922 may correspond to thetransmissions from regular users 1902. As illustrated in FIG. 20 withthe dashed-line arrow, regular uplink data 1922 may optionally betransmitted from the second subordinate entity 1904, depending on thecontents of the first resource assignment 1920 and whether the secondsubordinate entity 1904 is configured to transmit uplink datatransmissions utilizing the long TTI.

The blocks 2102 and 2104 may repeat, or be iterated a plurality of timesin various examples, as regular uplink data 1922 may continue to betransmitted from the subordinate entities. However, at any given time,it may arise that the scheduling entity 1901 may wish to transmit LoLatdata to a particular subordinate entity (i.e., the LoLat user 1904).Accordingly, at block 2106, the scheduling entity 1901 may transmit anassignment or grant 1912 of time-frequency resources on the LoLat grantchannel 1910 on the secondary TDD component carrier, to at least onesubordinate entity (e.g., the LoLat user 1904). Here, the resourceassignment 1912 may indicate for the LoLat user 1904 to receive LoLatdownlink data from the scheduling entity 1901 utilizing at least oneshort TTI. Specifically, the resource assignment 1912 may includeinformation identifying a particular subordinate entity 1904, andinformation identifying time-frequency resources granted on the primaryTDD component carrier for the LoLat downlink transmission.

At block 2108, the scheduling entity 1901 may optionally (as indicatedby the dashed-line box 2108) transmit an uplink scheduling grantmodification 1924 on any suitable channel, e.g., on the secondary TDDcomponent carrier. Here, the uplink scheduling grant modification 1924may instruct the regular users such as the first subordinate entity1902, having granted time-frequency resources for long-TTI uplinktransmissions, to puncture their uplink transmissions during at leastone designated short TTI (i.e., the short TTI(s) corresponding to theLoLat grant 1912).

Block 2110 represents operations at one or more subordinate entities,such as regular users 1902 and LoLat user(s) 1904. That is, in responseto the uplink grant modification 1924, the regular users (e.g., thefirst subordinate entity 1902) may optionally puncture their previouslyscheduled uplink data transmissions that utilize the long TTI. Thepuncturing is an optional step, operable on subordinate entitiesconfigured to monitor the control channels on the secondary TDDcomponent carrier while transmitting uplink data on the primary TDDcomponent carrier.

At block 2112, in accordance with the resource assignment 1912, thescheduling entity 1901 may transmit the LoLat downlink data 1926 on theprimary TDD component carrier. In some examples, the transmission of theLoLat grant 1912 and the LoLat downlink data 1926 may occur at the sametime, i.e., during the same short TTI. However, this is not necessarilythe case, and in other examples, the LoLat downlink grant 1912 and theLoLat downlink data may be transmitted during completely non-overlappingshort TTIs, or, as illustrated in FIG. 19, a single short TTI may beutilized for the LoLat downlink grant 1912, which may overlap with anynumber (including zero) of short TTIs during which the LoLat downlinkdata is transmitted on the primary TDD component carrier.

Blocks 2114 and 2116 represent operations at one or more subordinateentities, such as the regular users 1902 and, in some examples, LoLatuser(s) 1904. That is, at block 2114, the regular subordinate entitiesmay optionally wait for a suitable gap or guard time 1906, after the endof the scheduled LoLat downlink transmissions 1926. This guard time 1906may for example compensate for any propagation delay or other airinterface delay, allowing full completion of the LoLat downlinktransmissions to all users in the service area prior to resumption ofany uplink transmissions on the primary TDD component carrier. At block2116, the regular subordinate entities (i.e., regular user 1902) mayresume their regular uplink data transmissions on the primary TDDcomponent carrier when transmission of the LoLat downlink data has beencompleted (and optionally after the guard time 1906). Accordingly, atblock 2118, the scheduling entity 1902 may resume receiving regularuplink data on the primary TDD component carrier from one or moresubordinate entities utilizing the long TTI.

By utilizing the above scheme, pairing primary and secondary TDDcomponent carriers, a thin LoLat grant channel 1912 can enable ascheduling entity to rapidly and dynamically control the multiplexing ofuplink and downlink data on the primary TDD component carrier having atleast two different data types or categories, from a set of subordinateentities.

TDD-TDD Carrier Pairing: Multiplexing LoLat UL on Regular DL

FIG. 22 illustrates yet another example of pairing primary and secondaryTDD component carriers, providing for multiplexing of LoLat uplinktransmissions (i.e., transmissions from a subordinate entity) withregular downlink transmissions (i.e., transmissions from a schedulingentity). In the illustrated example, the primary TDD component carrieris illustrated in much the same way as the TDD carrier in FIG. 8, withdownlink resources shown with a scheduling entity transmitting regulardownlink data utilizing a long TTI to plurality of users (subordinateentities). Here, as will be described in further detail below, at therequest of a subordinate entity, the scheduling entity may modify thescheduling assignment or grant of time-frequency resources, interruptingthe ongoing downlink transmissions on the primary TDD component carrier,to enable uplink transmissions (e.g., LoLat data transmissions) on theprimary TDD component carrier.

In the illustrated example, control channels for controlling the datacarried on the primary TDD component carrier may be carried on either orboth of the primary and/or secondary TDD component carriers. Forexample, as illustrated the primary TDD component carrier includes aLoLat grant channel 2212 in which a subordinate entity may receiveinformation such as a LoLat uplink grant 2214, which may carry grantinformation for the LoLat user 2204 that requested LoLat scheduling toutilize for transmitting a LoLat uplink transmission. The primary TDDcomponent carrier further includes a thin control channel 2216 that maycarry a downlink grant modification 2218, which modifies a downlinktime-frequency resource grant corresponding to the regular users' 2202downlink data reception on the primary TDD component carrier.

In the illustration, the LoLat grant 2214 is shown as occupying a widerbandwidth than the DL grant modification 2218. This represents that,while the DL grant modification 2218 may simply be a few bitsrepresenting the frequency resources that are being re-allocated awayfrom a regular user 2202, and a number of short TTIs, the LoLat grant2214 may include more precise information relating to the LoLat resourceassignment such as a user ID, the assignment information, a modulationand coding scheme, etc.

Furthermore, a control channel for enabling subordinate entities toquickly send information to the scheduling entity is carried on thesecondary TDD component carrier. That is, the secondary TDD componentcarrier includes a thin feedback channel 2208 in which the schedulingentity may receive feedback information from subordinate entities suchas a LoLat scheduling request 2210.

In addition to the illustrated channels, time-frequency resourcescorresponding to the long TTI may be granted for downlink transmissionson the primary TDD component carrier to one or more subordinate entities(e.g., Users A-F) by utilizing any suitable downlink grant channel (notnecessarily one of the illustrated channels). As these downlinktransmissions are ongoing, if a particular subordinate entity, denotedas the LoLat user 2204, wishes to request resources for a LoLat uplinktransmission, this subordinate entity may transmit a LoLat schedulingrequest 2210 on the thin feedback channel 2208 on the secondary TDDcomponent carrier. Here, the LoLat scheduling request 2210 may utilizethe short TTI, although this is not necessarily always the case. Inresponse, if the scheduling entity wishes to grant the requested LoLatresource, the scheduling entity 102 may transmit, on the primary TDDcomponent carrier, a LoLat grant 2214 that informs the LoLat user 2204that transmitted the LoLat user scheduling request 2210 of its grantedresources. After a suitable delay to enable the LoLat user to receiveand process the LoLat grant 2214 and prepare for its LoLat uplinktransmission, the scheduling entity may further transmit, on the thincontrol channel 2216, a downlink grant modification 2218 that informsthe regular users 2202 that are receiving downlink data transmissions onthe primary TDD component carrier, that some or all of their grantedresources are being modified or removed to make way for the LoLattransmission.

Because the data carrier is a TDD carrier, during transmission of theuplink data by the LoLat user 2204, the downlink data transmissions tothe regular users 2202 utilizing the long TTI are punctured, ceased, orsuspended. During this time, the LoLat user 2204 may transmit its LoLatuplink transmission on the primary TDD component carrier, resulting inan orthogonal multiple access scheme between regular downlinktransmissions and LoLat uplink transmissions on the primary TDDcomponent carrier.

In some examples, just prior to the time at which LoLat uplinktransmissions are scheduled to commence, the scheduling entity maysuspend its regular downlink data transmissions on the primary TDDcomponent carrier. That is, a gap or guard time 2206 may optionally beutilized when multiplexing LoLat uplink transmissions and regulardownlink transmissions on the primary TDD component carrier. Here, thisguard time 2206 may for example compensate for any propagation delay orother air interface delay, allowing full completion of the regulardownlink transmissions to all users in the service area prior to thetime when the LoLat uplink transmissions commence on the primary TDDcomponent carrier.

In the illustration, the downlink grant modification 2218 is illustratedas appearing at the same time as the downlink resources are modified.The need for advance timing of the grant modification can be avoidedbecause the downlink grant modification 2218 and the downlink data maybe buffered and post-processed by the receiving regular users 2202, asdescribed above.

FIG. 23 is a call flow diagram illustrating an exemplary resourceassignment and re-assignment procedure as it might occur in accordancewith one example for multiplexing uplink and downlink data withdifferent latency targets utilizing a paired set of primary andsecondary TDD component carriers. In this illustration, time movesforward in the downward direction, and communication signals between theillustrated entities are denoted with arrows between the lines below therespective entities. As illustrated, a scheduling entity 2201 is incommunication with a plurality of subordinate entities 104, including aregular user 2202 and a LoLat user 2204. Each entity 2201, 2202, and2204 is configured for communication over primary and secondary TDDcomponent carriers. The respective primary and secondary TDD componentcarriers are illustrated schematically with the two vertical linesextending down from each respective entity.

FIG. 23 is described below in conjunction with a flow chart illustratedin FIG. 24. That is, FIG. 24 is a flow chart illustrating an exemplaryprocess 2400 for resource assignment and re-assignment utilizing apaired set of primary and secondary TDD carriers in accordance with someaspects of the present disclosure. The process 2400 is described fromthe point-of-view of a scheduling entity 2201, and may accordingly, asdescribed in conjunction with FIG. 23, be operational at the schedulingentity 102 described above in conjunction with FIGS. 1 and/or 2. Inother examples within the scope of the present disclosure, the process2400 may be operational by a general purpose processor, a processingsystem 214 as described above and illustrated in FIG. 2, or any suitablemeans for carrying out the described functions. The specific order ofsteps or blocks shown in FIG. 24 is merely exemplary in nature, and invarious aspects of the disclosure, these steps or blocks may occur inany suitable order, with some examples including two or more steps orblocks occurring simultaneously.

At block 2402, the scheduling entity 2201 may transmit a firstassignment or grant 2220 of time-frequency resources to at least onesubordinate entity on the secondary TDD component carrier. Any suitablecontrol channel on the secondary TDD component carrier (or, in someexamples, on the primary TDD component carrier) may be utilized for thefirst resource assignment 2220, such as a downlink assignment channel.Here, the first resource assignment 2220 may be configured to indicatewhich time-frequency resource or resources are assigned to therespective subordinate entities for receiving regular transmissions ofdownlink data, that is, transmissions utilizing the long TTI. Inaccordance with the first resource assignment 2220, at block 2404, thescheduling entity 2201 may transmit regular downlink data 2222 on theprimary TDD component carrier to the at least one subordinate entity(e.g., the subordinate entities 2202 and 2204) utilizing the long TTI.Here, with reference to FIG. 22, this regular uplink data 2222 maycorrespond to the downlink transmissions to regular users 2202. Asillustrated in FIG. 23 with the dashed-line arrow, regular downlink data2222 may optionally be transmitted to the second subordinate entity2204, depending on the contents of the first resource assignment 2220and whether the second subordinate entity 2204 is configured to receivedownlink data transmissions utilizing the long TTI.

The blocks 2402 and 2404 may repeat, or be iterated a plurality of timesin various examples, as regular downlink data 2222 may continue to betransmitted to the subordinate entities. However, at any given time, itmay arise that the subordinate entity 2204 (i.e., the LoLat user 2204)may wish to transmit LoLat uplink data to the scheduling entity 2201.Accordingly, at block 2406, the scheduling entity 2201 may receive aLoLat scheduling request 2210 on the thin feedback channel 2208 on thesecondary TDD component carrier from the LoLat user 2204 (i.e., thesecond subordinate entity 2204). The LoLat scheduling request 2210 mayinclude information identifying the requesting subordinate entity 2204,and including any pertinent information relating to the LoLat datadesired to be transmitted.

At block 2408, the scheduling entity 2201 may transmit a secondassignment or grant 2214 of time-frequency resources on a LoLat grantchannel 2212 on the primary TDD component carrier, to the requestingsubordinate entity 2204. Here, the second resource assignment 2214 mayinclude information identifying the requesting subordinate entity 2204,and information identifying time-frequency resources granted on the TDDuplink carrier for the LoLat uplink transmission.

At optional block 2410, the scheduling entity 2201 may suspend itsregular downlink data transmissions 2222 on the primary TDD componentcarrier just prior to the time at which LoLat uplink transmissions 2224are scheduled to commence. That is, a gap or guard time 2206 mayoptionally be utilized when multiplexing LoLat uplink transmissions 2224and regular downlink transmissions 2222 on the primary TDD componentcarrier.

At block 2412, the scheduling entity 2201 may transmit a downlinkscheduling grant modification 2218 on the thin control channel 2216 onthe primary TDD component carrier. Here, the downlink scheduling grantmodification 2218 may instruct the regular users such as the firstsubordinate entity 2202, having granted time-frequency resources forlong-TTI downlink transmissions, to ignore any uplink transmissionsduring at least one designated short TTI. That is, since thetransmissions during that TTI will be LoLat uplink transmissions 2224from the LoLat user 2204, not directed to the regular user 2202, thedata may not be decodable by the regular user 2202 and can be ignored bythe regular user 2202 during post-processing of the corresponding longTTI.

Block 2414 represents operations at one or more subordinate entities,such as the LoLat user 2204. That is, in response to the second resourceassignment 2214, the LoLat user (i.e., the second subordinate entity2204) may transmit the LoLat uplink data 2224 utilizing the assignedtime-frequency resources on the primary TDD component carrier.

In some examples, the transmission of the downlink scheduling grantmodification 2218 at block 2412, and the transmission of the LoLatuplink data 2224 on the primary TDD component carrier at block 2414 (andthe corresponding suspension of downlink data transmissions on theprimary TDD component carrier, not including any guard time that may beadded), may occur simultaneously. While this may violate orthogonality,the regular users may be suitably configured to ignore the informationcorresponding to the time-frequency resources allocated to the LoLatuser 2204 during post-processing, as indicated in the downlink grantmodification 2218. In other examples, these transmissions may be atdifferent times, according to the details of a particularimplementation. That is, the regular users 2202 may be configured tobuffer or cache the contents of the thin control channel 2216 and theprimary TDD component carrier, such that the ignoring of data during thedesignated short TTI(s) may be performed during post-processing by theregular users 2202.

At block 2416, the scheduling entity 2201 may receive the LoLat uplinkdata 2224 transmitted from the requesting subordinate entity 2204utilizing the short TTI on the primary TDD component carrier. At block2418, the scheduling entity 2201 may resume transmitting the regulardownlink data 2222 on the primary TDD component carrier, to one or moresubordinate entities, such as the regular user 2202 utilizing the longTTI.

By utilizing the above scheme, pairing primary and secondary TDDcomponent carriers, a thin control channel 2216 and thin feedbackchannel 2208 can enable a scheduling entity to multiplex uplink anddownlink data having at least two different data types or categories,for set of subordinate entities.

Referring now to FIG. 25, a flow chart is provided illustrating anexemplary process 2500 of wireless communication utilizing a TDD carrierpaired with a second carrier, and multiplexing long and short TTIs,according to some aspects of the disclosure. In various examples, theprocess 2500 may be implemented by the scheduling entity 102 illustratedin FIGS. 1 and 2; the scheduling entities 501, 801, 1101, 1601, 1901, or2201 illustrated in FIGS. 5, 8, 11, 16, 19, and 22, respectively; by aprocessing system 214 including a processor 204; or by any suitablemeans for carrying out the described functions.

At block 2502, a scheduling entity 102 may wirelessly communicate withone or more subordinate entities 104 utilizing a first (e.g., long) TTIover a TDD carrier. Here, wirelessly communicating may includetransmitting and/or receiving data and/or control information on one ormore communication channels, as described above. Further, at block 2504,the scheduling entity 102 may wirelessly communicate utilizing a second(e.g., short) TTI that at least partially overlaps with the long TTI,utilizing a second carrier paired with the first carrier but separatedfrom the first carrier in frequency. Here, the second, paired carriermay be an FDD carrier or a TDD carrier.

Referring now to FIG. 26, flow chart is provided illustrating anexemplary process 2600 of wireless communication utilizing a pair of TDDcarriers for full duplex communication, according to some aspects of thedisclosure. In various examples, the process 2600 may be implemented bythe scheduling entity 102 illustrated in FIGS. 1 and 2; the schedulingentities 501, 801, 1101, 1601, 1901, or 2201 illustrated in FIGS. 5, 8,11, 16, 19, and 22, respectively; by a processing system 214 including aprocessor 204; or by any suitable means for carrying out the describedfunctions.

At block 2602, a scheduling entity 102 may wirelessly communicate over afirst TDD carrier. Here, wirelessly communicating may includetransmitting and/or receiving data and/or control information on one ormore communication channels, as described above. Further, at block 2604,the scheduling entity 102 may wirelessly communicate over a second TDDcarrier paired with the first TDD carrier, but separated from the firstTDD carrier in frequency. Here, at least a portion of time slots in thefirst TDD carrier may be complementary in direction to a direction oftime-aligned time slots in the second TDD carrier. That is, at least oneuplink time slot in the first TDD carrier may be time-aligned with adownlink time slot in the second TDD carrier.

As those skilled in the art will readily appreciate, various aspectsdescribed throughout this disclosure may be extended to any suitabletelecommunication systems, network architectures and communicationstandards. By way of example, various aspects may be applied to UMTSsystems such as W-CDMA, TD-SCDMA, and TD-CDMA. Various aspects may alsobe applied to systems employing Long Term Evolution (LTE) (in FDD, TDD,or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both modes),CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile Broadband(UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20,Ultra-Wideband (UWB), Bluetooth, and/or other suitable systems,including those described by yet-to-be defined wide area networkstandards. The actual telecommunication standard, network architecture,and/or communication standard employed will depend on the specificapplication and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean“serving as an example, instance, or illustration.” Any implementationor aspect described herein as “exemplary” is not necessarily to beconstrued as preferred or advantageous over other aspects of thedisclosure. Likewise, the term “aspects” does not require that allaspects of the disclosure include the discussed feature, advantage ormode of operation. The term “coupled” is used herein to refer to thedirect or indirect coupling between two objects. For example, if objectA physically touches object B, and object B touches object C, thenobjects A and C may still be considered coupled to one another—even ifthey do not directly physically touch each other. For instance, a firstdie may be coupled to a second die in a package even though the firstdie is never directly physically in contact with the second die. Theterms “circuit” and “circuitry” are used broadly, and intended toinclude both hardware implementations of electrical devices andconductors that, when connected and configured, enable the performanceof the functions described in the present disclosure, without limitationas to the type of electronic circuits, as well as softwareimplementations of information and instructions that, when executed by aprocessor, enable the performance of the functions described in thepresent disclosure.

One or more of the components, steps, features and/or functionsillustrated in FIGS. 1-26 may be rearranged and/or combined into asingle component, step, feature or function or embodied in severalcomponents, steps, or functions. Additional elements, components, steps,and/or functions may also be added without departing from novel featuresdisclosed herein. The apparatus, devices, and/or components illustratedin FIGS. 1-26 may be configured to perform one or more of the methods,features, or steps described herein. The novel algorithms describedherein may also be efficiently implemented in software and/or embeddedin hardware.

It is to be understood that the specific order or hierarchy of steps inthe methods disclosed is an illustration of exemplary processes. Basedupon design preferences, it is understood that the specific order orhierarchy of steps in the methods may be rearranged. The accompanyingmethod claims present elements of the various steps in a sample order,and are not meant to be limited to the specific order or hierarchypresented unless specifically recited therein.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but are to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. A phrase referring to“at least one of” a list of items refers to any combination of thoseitems, including single members. As an example, “at least one of: a, b,or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, band c. All structural and functional equivalents to the elements of thevarious aspects described throughout this disclosure that are known orlater come to be known to those of ordinary skill in the art areexpressly incorporated herein by reference and are intended to beencompassed by the claims. Moreover, nothing disclosed herein isintended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. § 112(f), unless theelement is expressly recited using the phrase “means for” or, in thecase of a method claim, the element is recited using the phrase “stepfor.”

What is claimed is:
 1. A method of wireless communication operable at asubordinate entity, comprising: wirelessly communicating with ascheduling entity utilizing a first transmission time interval (TTI)over a first carrier, the first carrier being a time division duplex(TDD) carrier; wirelessly communicating with the scheduling entityutilizing a second TTI shorter in duration than the first TTI andoverlapping a portion of the first TTI, over a second carrier pairedwith the first carrier and separated from the first carrier infrequency; and receiving a control channel utilizing the second TTI overthe second carrier, the control channel comprising informationconfigured to modify data communication on the first carrier utilizingthe first TTI with other data communication utilizing the second TTI. 2.The method of claim 1, wherein the second carrier is a frequencydivision duplex (FDD) carrier.
 3. The method of claim 2, furthercomprising: transmitting a scheduling request to the scheduling entityon a feedback channel on the FDD carrier; receiving an uplink grant fromthe scheduling entity on the FDD carrier in response to the schedulingrequest, the uplink grant configured to identify granted resources onthe TDD carrier for an uplink data transmission utilizing the secondTTI; and transmitting the uplink data to the scheduling entity utilizingthe second TTI in accordance with the uplink grant.
 4. The method ofclaim 2, further comprising: receiving from the scheduling entity agrant modification via the control channel on the FDD carrier, the grantmodification configured to modify an existing grant of resources for anuplink data transmission utilizing the first TTI; and driving a zeroinput to a power amplifier associated with a transceiver to suspenduplink transmissions in accordance with the grant modification.
 5. Themethod of claim 2, further comprising: receiving a downlink grant fromthe scheduling entity on a grant channel on the FDD carrier utilizingthe second TTI; and receiving downlink data corresponding to thedownlink grant from the scheduling entity on the TDD carrier utilizingthe second TTI.
 6. The method of claim 5, wherein the downlink grant andthe downlink data corresponding to the downlink grant are receivedsimultaneous to one another.
 7. The method of claim 2, furthercomprising: receiving and buffering a downlink grant from the schedulingentity on a grant channel on the FDD carrier utilizing the second TTI,while transmitting uplink data on the TDD carrier.
 8. The method ofclaim 2, further comprising: receiving from the scheduling entity agrant modification via the control channel on the FDD carrier, the grantmodification configured to modify an existing grant of resources fordownlink data utilizing the first TTI; and modifying reception of thedownlink data on the TDD carrier utilizing the first TTI in accordancewith the grant modification.
 9. The method of claim 8, wherein themodifying reception of the downlink data comprises suspending receptionof the downlink data during at least one second TTI.
 10. The method ofclaim 1, wherein the second carrier is a TDD carrier having a conjugatepairing with the first carrier, wherein at least a portion of time slotsin the first carrier are complementary in direction to a direction oftime-aligned time slots in the second carrier.
 11. The method of claim10, further comprising: transmitting a scheduling request to ascheduling entity on a feedback channel on the first carrier; receivingan uplink grant from the scheduling entity on the second carrier inresponse to the scheduling request, the uplink grant configured toidentify granted resources on the first carrier for an uplink datatransmission utilizing the second TTI; and transmitting the uplink datato the scheduling entity utilizing the second TTI in accordance with theuplink grant.
 12. The method of claim 10, further comprising: receivinga grant modification on the second carrier, the grant modificationconfigured to modify an existing grant of resources for an uplink datatransmission utilizing the first TTI; and modifying the uplink datatransmission in accordance with the grant modification.
 13. The methodof claim 12, wherein the modifying the uplink data comprises suspendingtransmission of the uplink data.
 14. The method of claim 10, furthercomprising: receiving a downlink grant from a scheduling entity on agrant channel on the second carrier utilizing the second TTI; andreceiving downlink data corresponding to the downlink grant, from thescheduling entity on the first carrier utilizing the second TTI.
 15. Themethod of claim 14, wherein the downlink grant and the downlink data arereceived simultaneous to one another.
 16. The method of claim 10,further comprising: receiving and buffering a downlink grant from ascheduling entity on a grant channel on the second carrier utilizing thesecond TTI, while transmitting uplink data on the first carrierutilizing the first TTI.
 17. The method of claim 10, further comprising:transmitting a scheduling request to a scheduling entity on a feedbackchannel on the second carrier; receiving an uplink grant from thescheduling entity in response to the scheduling request, the uplinkgrant configured to identify granted resources on the first carrier foran uplink data transmission utilizing the second TTI; and transmittingthe uplink data to the scheduling entity utilizing the second TTI on thefirst carrier in accordance with the uplink grant.
 18. The method ofclaim 17, wherein the grant modification and the downlink data arereceived simultaneous to one another.
 19. The method of claim 10,further comprising: receiving from the scheduling entity a grantmodification on the first carrier, the grant modification configured tomodify an existing grant of resources for downlink data utilizing thefirst TTI; and modifying reception of the downlink data on the secondcarrier utilizing the first TTI in accordance with the grantmodification.
 20. The method of claim 19, wherein the modifyingreception of the downlink data comprises suspending reception of thedownlink data during at least one second TTI.
 21. A subordinate entityconfigured for wireless communication, comprising: at least oneprocessor; a non-transitory computer-readable medium communicativelycoupled to the at least one processor; and a transceiver communicativelycoupled to the at least one processor, wherein the at least oneprocessor is configured to: utilize the transceiver to wirelesslycommunicate with a scheduling entity utilizing a first transmission timeinterval (TTI) over a first carrier, the first carrier being a timedivision duplex (TDD) carrier; utilize the transceiver to wirelesslycommunicate with the scheduling entity utilizing a second TTI shorter induration than the first TTI and overlapping a portion of the first TTI,over a second carrier paired with the first carrier and separated fromthe first carrier in frequency; and utilize a control channel of thesecond carrier to modify data communication on the first carrierutilizing the first TTI with other data communication utilizing thesecond TTI.
 22. The subordinate entity of claim 21, wherein the secondcarrier is a frequency division duplex (FDD) carrier.
 23. Thesubordinate entity of claim 22, wherein the at least one processor isfurther configured to: utilize the transceiver to transmit a schedulingrequest to the scheduling entity on a feedback channel on the FDDcarrier; utilize the transceiver to receive an uplink grant from thescheduling entity on the FDD carrier in response to the schedulingrequest, the uplink grant configured to identify granted resources onthe TDD carrier for an uplink data transmission utilizing the secondTTI; and utilize the transceiver to transmit the uplink data to thescheduling entity utilizing the second TTI in accordance with the uplinkgrant.
 24. The subordinate entity of claim 22, wherein the at least oneprocessor is further configured to: utilize the transceiver to receivefrom the scheduling entity a grant modification via the control channelon the FDD carrier, the grant modification configured to modify anexisting grant of resources for an uplink data transmission utilizingthe first TTI; and drive a zero input to a power amplifier associatedwith the transceiver to suspend uplink transmissions in accordance withthe grant modification.
 25. The subordinate entity of claim 22, whereinthe at least one processor is further configured to: utilize thetransceiver to receive a downlink grant from the scheduling entity on agrant channel on the FDD carrier utilizing the second TTI; and utilizethe transceiver to receive downlink data corresponding to the downlinkgrant from the scheduling entity on the TDD carrier utilizing the secondTTI.
 26. The subordinate entity of claim 25, wherein the downlink grantand the downlink data corresponding to the downlink grant are receivedsimultaneous to one another.
 27. The subordinate entity of claim 22,wherein the at least one processor is further configured to: utilize thetransceiver to receive a downlink grant from the scheduling entity on agrant channel on the FDD carrier utilizing the second TTI; and bufferthe downlink grant while transmitting uplink data on the TDD carrier.28. The subordinate entity of claim 22, wherein the at least oneprocessor is further configured to: utilize the transceiver to receivefrom the scheduling entity a grant modification via the control channelon the FDD carrier, the grant modification configured to modify anexisting grant of resources for downlink data utilizing the first TTI;and modify reception of the downlink data on the TDD carrier utilizingthe first TTI in accordance with the grant modification.
 29. Thesubordinate entity of claim 28, wherein the at least one processor,being configured to modify reception of the downlink data, is furtherconfigured to suspend reception of the downlink data during at least onesecond TTI.
 30. The subordinate entity of claim 21, wherein the secondcarrier is a TDD carrier having a conjugate pairing with the firstcarrier, wherein at least a portion of time slots in the first carrierare complementary in direction to a direction of time-aligned time slotsin the second carrier.
 31. The subordinate entity of claim 30, whereinthe at least one processor is further configured to: utilize thetransceiver to transmit a scheduling request to a scheduling entity on afeedback channel on the first carrier; utilize the transceiver toreceive an uplink grant from the scheduling entity on the second carrierin response to the scheduling request, the uplink grant configured toidentify granted resources on the first carrier for an uplink datatransmission utilizing the second TTI; and utilize the transceiver totransmit the uplink data to the scheduling entity utilizing the secondTTI in accordance with the uplink grant.
 32. The subordinate entity ofclaim 30, wherein the at least one processor is further configured to:utilize the transceiver to receive a grant modification on the secondcarrier, the grant modification configured to modify an existing grantof resources for an uplink data transmission utilizing the first TTI;and modify the uplink data transmission in accordance with the grantmodification.
 33. The subordinate entity of claim 32, wherein the atleast one processor, being configured to modify the uplink data, isfurther configured to suspend transmission of the uplink data.
 34. Thesubordinate entity of claim 30, wherein the at least one processor isfurther configured to: utilize the transceiver to receive a downlinkgrant from a scheduling entity on a grant channel on the second carrierutilizing the second TTI; and utilize the transceiver to receivedownlink data corresponding to the downlink grant, from the schedulingentity on the first carrier utilizing the second TTI.
 35. Thesubordinate entity of claim 34, wherein the at least one processor isfurther configured to receive the downlink grant and the downlink datasimultaneous to one another.
 36. The subordinate entity of claim 30,wherein the at least one processor is further configured to: utilize thetransceiver to receive a downlink grant from a scheduling entity on agrant channel on the second carrier utilizing the second TTI; and bufferthe downlink grant while transmitting uplink data on the first carrierutilizing the first TTI.
 37. The subordinate entity of claim 30, whereinthe at least one processor is further configured to: utilize thetransceiver to transmit a scheduling request to a scheduling entity on afeedback channel on the second carrier; utilize the transceiver toreceive an uplink grant from the scheduling entity in response to thescheduling request, the uplink grant configured to identify grantedresources on the first carrier for an uplink data transmission utilizingthe second TTI; and utilize the transceiver to transmit the uplink datato the scheduling entity utilizing the second TTI on the first carrierin accordance with the uplink grant.
 38. The subordinate entity of claim37, wherein the at least one processor is further configured to receivethe grant modification and the downlink data simultaneous to oneanother.
 39. The subordinate entity of claim 30, wherein the at leastone processor is further configured to: utilize the transceiver toreceive from the scheduling entity a grant modification on the firstcarrier, the grant modification configured to modify an existing grantof resources for downlink data utilizing the first TTI; and utilize thetransceiver to modify reception of the downlink data on the secondcarrier utilizing the first TTI in accordance with the grantmodification.
 40. The subordinate entity of claim 39, wherein the atleast one processor, being configured to modify reception of thedownlink data, is further configured to suspend reception of thedownlink data during at least one second TTI.
 41. A subordinate entityconfigured for wireless communication, comprising: means for wirelesslycommunicating with a scheduling entity utilizing a first transmissiontime interval (TTI) over a first carrier, the first carrier being a timedivision duplex (TDD) carrier; means for wirelessly communicating withthe scheduling entity utilizing a second TTI shorter in duration thanthe first TTI and overlapping a portion of the first TTI, over a secondcarrier paired with the first carrier and separated from the firstcarrier in frequency; and means for utilizing a control channel of thesecond carrier to modify data communication on the first carrierutilizing the first TTI with other data communication utilizing thesecond TTI.
 42. The subordinate entity of claim 41, wherein the secondcarrier is a frequency division duplex (FDD) carrier.
 43. Thesubordinate entity of claim 42, further comprising: means fortransmitting a scheduling request to the scheduling entity on a feedbackchannel on the FDD carrier; means for receiving an uplink grant from thescheduling entity on the FDD carrier in response to the schedulingrequest, the uplink grant configured to identify granted resources onthe TDD carrier for an uplink data transmission utilizing the secondTTI; and means for transmitting the uplink data to the scheduling entityutilizing the second TTI in accordance with the uplink grant.
 44. Thesubordinate entity of claim 42, further comprising: means for receivingfrom the scheduling entity a grant modification via the control channelon the FDD carrier, the grant modification configured to modify anexisting grant of resources for an uplink data transmission utilizingthe first TTI; and means for driving a zero input to a power amplifierassociated with a transceiver to suspend uplink transmissions inaccordance with the grant modification.
 45. The subordinate entity ofclaim 42, further comprising: means for receiving a downlink grant fromthe scheduling entity on a grant channel on the FDD carrier utilizingthe second TTI; and means for receiving downlink data corresponding tothe downlink grant from the scheduling entity on the TDD carrierutilizing the second TTI.
 46. The subordinate entity of claim 45,wherein the means for receiving the downlink grant and the means forreceiving the downlink data corresponding to the downlink grant areconfigured to receive the downlink grant and the downlink datasimultaneous to one another.
 47. The subordinate entity of claim 42,further comprising: means for receiving and buffering a downlink grantfrom the scheduling entity on a grant channel on the FDD carrierutilizing the second TTI while transmitting uplink data on the TDDcarrier.
 48. The subordinate entity of claim 42, further comprising:means for receiving from the scheduling entity a grant modification viathe control channel on the FDD carrier, the grant modificationconfigured to modify an existing grant of resources for downlink datautilizing the first TTI; and means for modifying reception of thedownlink data on the TDD carrier utilizing the first TTI in accordancewith the grant modification.
 49. The subordinate entity of claim 48,wherein the means for modifying reception of the downlink data isconfigured for suspending reception of the downlink data during at leastone second TTI.
 50. The subordinate entity of claim 41, wherein thesecond carrier is a TDD carrier having a conjugate pairing with thefirst carrier, wherein at least a portion of time slots in the firstcarrier are complementary in direction to a direction of time-alignedtime slots in the second carrier.
 51. The subordinate entity of claim50, further comprising: means for transmitting a scheduling request to ascheduling entity on a feedback channel on the first carrier; means forreceiving an uplink grant from the scheduling entity on the secondcarrier in response to the scheduling request, the uplink grantconfigured to identify granted resources on the first carrier for anuplink data transmission utilizing the second TTI; and means fortransmitting the uplink data to the scheduling entity utilizing thesecond TTI in accordance with the uplink grant.
 52. The subordinateentity of claim 50, further comprising: means for receiving a grantmodification on the second carrier, the grant modification configured tomodify an existing grant of resources for an uplink data transmissionutilizing the first TTI; and means for modifying the uplink datatransmission in accordance with the grant modification.
 53. Thesubordinate entity of claim 52, wherein the means for modifying theuplink data are configured for suspending transmission of the uplinkdata.
 54. The subordinate entity of claim 50, further comprising: meansfor receiving a downlink grant from a scheduling entity on a grantchannel on the second carrier utilizing the second TTI; and means forreceiving downlink data corresponding to the downlink grant, from thescheduling entity on the first carrier utilizing the second TTI.
 55. Thesubordinate entity of claim 54, wherein the means for receiving thedownlink grant and the means for receiving the downlink data areconfigured to receive the downlink grant and the downlink datasimultaneous to one another.
 56. The subordinate entity of claim 50,further comprising: means for receiving and buffering a downlink grantfrom a scheduling entity on a grant channel on the second carrierutilizing the second TTI, while transmitting uplink data on the firstcarrier utilizing the first TTI.
 57. The subordinate entity of claim 50,further comprising: means for transmitting a scheduling request to ascheduling entity on a feedback channel on the second carrier; means forreceiving an uplink grant from the scheduling entity in response to thescheduling request, the uplink grant configured to identify grantedresources on the first carrier for an uplink data transmission utilizingthe second TTI; and means for transmitting the uplink data to thescheduling entity utilizing the second TTI on the first carrier inaccordance with the uplink grant.
 58. The subordinate entity of claim57, wherein the means for receiving the grant modification and the meansfor receiving the downlink data are configured to receive the grantmodification and the downlink data simultaneous to one another.
 59. Thesubordinate entity of claim 50, further comprising: means for receivingfrom the scheduling entity a grant modification on the first carrier,the grant modification configured to modify an existing grant ofresources for downlink data utilizing the first TTI; and means formodifying reception of the downlink data on the second carrier utilizingthe first TTI in accordance with the grant modification.
 60. Thesubordinate entity of claim 59, wherein the means for modifyingreception of the downlink data are configured for suspending receptionof the downlink data during at least one second TTI.
 61. Anon-transitory computer-readable medium storing computer-executable codeon a subordinate entity comprising at least one processor configured forwireless communication, comprising: instructions for causing a computerto wirelessly communicate with a scheduling entity utilizing a firsttransmission time interval (TTI) over a first carrier, the first carrierbeing a time division duplex (TDD) carrier; instructions for causing acomputer to wirelessly communicate with the scheduling entity utilizinga second TTI shorter in duration than the first TTI and at leastpartially overlapping the first TTI, over a second carrier paired withthe first carrier and separated from the first carrier in frequency; andinstructions for causing a computer to utilize a control channel of thesecond carrier to modify data communication on the first carrierutilizing the first TTI with other data communication utilizing thesecond TTI.
 62. The computer-readable medium of claim 61, wherein thesecond carrier is a frequency division duplex (FDD) carrier.
 63. Thecomputer-readable medium of claim 62, further comprising: instructionsfor causing a computer to transmit a scheduling request to thescheduling entity on a feedback channel on the FDD carrier; instructionsfor causing a computer to receive an uplink grant from the schedulingentity on the FDD carrier in response to the scheduling request, theuplink grant configured to identify granted resources on the TDD carrierfor an uplink data transmission utilizing the second TTI; andinstructions for causing a computer to transmit the uplink data to thescheduling entity utilizing the second TTI in accordance with the uplinkgrant.
 64. The computer-readable medium of claim 62, further comprising:instructions for causing a computer to receive from the schedulingentity a grant modification via the control channel on the FDD carrier,the grant modification configured to modify an existing grant ofresources for an uplink data transmission utilizing the first TTI; andinstructions for causing a computer to drive a zero input to a poweramplifier associated with a transceiver to suspend uplink transmissionsin accordance with the grant modification.
 65. The computer-readablemedium of claim 62, further comprising: instructions for causing acomputer to receive a downlink grant from the scheduling entity on agrant channel on the FDD carrier utilizing the second TTI; andinstructions for causing a computer to receive downlink datacorresponding to the downlink grant from the scheduling entity on theTDD carrier utilizing the second TTI.
 66. The computer-readable mediumof claim 65, wherein the instructions for causing a computer to receivea downlink grant and the instructions for causing a computer to receivedownlink data corresponding to the downlink grant are configured toreceive the downlink grant and the downlink data simultaneous to oneanother.
 67. The computer-readable medium of claim 62, furthercomprising: instructions for causing a computer to receive and buffer adownlink grant from the scheduling entity on a grant channel on the FDDcarrier utilizing the second TTI, while transmitting uplink data on theTDD carrier.
 68. The computer-readable medium of claim 62, furthercomprising: instructions for causing a computer to receive from thescheduling entity a grant modification via the control channel on theFDD carrier, the grant modification configured to modify an existinggrant of resources for downlink data utilizing the first TTI; andinstructions for causing a computer to modify reception of the downlinkdata on the TDD carrier utilizing the first TTI in accordance with thegrant modification.
 69. The computer-readable medium of claim 68,wherein the instructions for causing a computer to modify reception ofthe downlink data are further configured for suspending reception of thedownlink data during at least one second TTI.
 70. The computer-readablemedium of claim 61, wherein the second carrier is a TDD carrier having aconjugate pairing with the first carrier, wherein at least a portion oftime slots in the first carrier are complementary in direction to adirection of time-aligned time slots in the second carrier.
 71. Thecomputer-readable medium of claim 70, further comprising: instructionsfor causing a computer to transmit a scheduling request to a schedulingentity on a feedback channel on the first carrier; instructions forcausing a computer to receive an uplink grant from the scheduling entityon the second carrier in response to the scheduling request, the uplinkgrant configured to identify granted resources on the first carrier foran uplink data transmission utilizing the second TTI; and instructionsfor causing a computer to transmit the uplink data to the schedulingentity utilizing the second TTI in accordance with the uplink grant. 72.The computer-readable medium of claim 70, further comprising:instructions for causing a computer to receive a grant modification onthe second carrier, the grant modification configured to modify anexisting grant of resources for an uplink data transmission utilizingthe first TTI; and instructions for causing a computer to modify theuplink data transmission in accordance with the grant modification. 73.The computer-readable medium of claim 72, wherein the instructions forcausing a computer to modify the uplink data are further configured forsuspending transmission of the uplink data.
 74. The computer-readablemedium of claim 70, further comprising: instructions for causing acomputer to receive a downlink grant from a scheduling entity on a grantchannel on the second carrier utilizing the second TTI; and instructionsfor causing a computer to receive downlink data corresponding to thedownlink grant, from the scheduling entity on the first carrierutilizing the second TTI.
 75. The computer-readable medium of claim 74,wherein the instructions for causing a computer to receive a downlinkgrant and the instructions for causing a computer to receive downlinkdata are configured to receive the downlink grant and the downlink datasimultaneous to one another.
 76. The computer-readable medium of claim70, further comprising: instructions for causing a computer to receiveand buffer a downlink grant from a scheduling entity on a grant channelon the second carrier utilizing the second TTI, while transmittinguplink data on the first carrier utilizing the first TTI.
 77. Thecomputer-readable medium of claim 70, further comprising: instructionsfor causing a computer to transmit a scheduling request to a schedulingentity on a feedback channel on the second carrier; instructions forcausing a computer to receive an uplink grant from the scheduling entityin response to the scheduling request, the uplink grant configured toidentify granted resources on the first carrier for an uplink datatransmission utilizing the second TTI; and instructions for causing acomputer to transmit the uplink data to the scheduling entity utilizingthe second TTI on the first carrier in accordance with the uplink grant.78. The computer-readable medium of claim 77, wherein the instructionsfor causing a computer to receive a grant modification and theinstructions for causing a computer to receive downlink data areconfigured to receive the grant modification and the downlink datasimultaneous to one another.
 79. The computer-readable medium of claim70, further comprising: instructions for causing a computer to receivefrom the scheduling entity a grant modification on the first carrier,the grant modification configured to modify an existing grant ofresources for downlink data utilizing the first TTI; and instructionsfor causing a computer to modify reception of the downlink data on thesecond carrier utilizing the first TTI in accordance with the grantmodification.
 80. The computer-readable medium of claim 79, wherein theinstructions for causing a computer to modify reception of the downlinkdata are further configured for suspending reception of the downlinkdata during at least one second TTI.